VOL. 94 DECEMBER, 1970 TRANSACTIONS OF THE ROYAL SOCIETY OF SOUTH AUSTRALIA INCORPORATED ADELAIDE PUBLISHED AND SOLD AT THE SOCIETY’S ROOMS STATE LIBRARY BUILDINGS NORTH TERRACE, ADELAIDE Registered at the G.P.O., Adelaide, for transmission by post as a periodical and printed at The Griffin Press, Netley, South Australia. CONTENTS Brran McGowran: Late paleocene in the ey Basin: biostratigraphy and the age of key microfaunas - - : : x - : . Crare R. Murpry and Janice R. Smiru: Age determination of pouch young and juvenile Kangaroo Island wallabies - : : ; ‘ : F, Deprenne; A revision of Australian genera of Archaeocyatha - - - RoBert F. G. SwinsourneE: A new species of Pelargonium L’Her ex Ait in South Australia - - 2 = : : k ib Mts : : C. R. Twwate, JeNnireR A. SHEPHERD, and Ropyn M, THomson; Geo- morphology of the southern part of the Arcoona Plateau and the Tent Hill region west and north of Port Augusta - - - - - - A. Tamuty: Physical and chemical tommaplogy of the Blue Lake of Mount Gambier, South Australia - - - - f : E 7 Mary Wane: The Stat grate distribution of the Ediacara fauna in Aus- tralia - - - = 3 Fi 2 - : : e, S. A. SHEPHERD and H. B. S. Womerstey: The sublittoral ecology of West Island, South Australia: 1. Environmental features and algal ecology - S. A. SHEPHERD and JEANETTE E. Watson: The sublittoral ecology of West Island, South Australia: 2. The association between hydroids and algal substrate - - - - - - - - - - - - Haroip W. Manter: A new genus of Trematode ( Digenea; Gorgoderidae ) from the ureter of the tuna ge (Thynnus thynnus maccoyii) in Aus- tralia - - - - - - - - - - - - WituiAM J. Sruart: The Cainozoic stratigraphy of the south eastern coastal area of Yorke Peninsula, South Australia - - - - : : SusAN BARKER: vena Station, South easels a field context for applied rangeland research - - - 3 : : _ B. P. Tuomson: A review of the Precambrian and lower Palaeozoic tectonics of South Australia = 4 . = = kn 2 : ! . Parricta M. Mawson: Skrjabinoptera goldmanae n.sp. (Nematoda Physa- lopteridae) from an Australian Agamid lizard - - - 2 = R. F. Parsons: Mallee vegetation of the southern Nullarbor and Roe Plains, Australia - - - - : : - 2 = - . J. R. Maconocur and R. T. Lance: Canopy dynamics of trees and shrubs with particular reference to the arid-zone topfeed species - - - Obituary: Francis John Mitchell, 1929-1970 - : : : “ - General Account, Library Account = - - : : 2 es 4 X Endowment and Scientific Research Fund - : : r = E 3 Report on the Activities of the Council - : 2 : 2 J 3 Officers for 1969-70 - - : : : ~ 2 : A s Awards of the Sir Joseph Verco Medal 1970 - : L = : : 105 139 LATE PALEOCENE IN THE OTWAY BASIN: BIOSTRATIGRAPHY AND AGE OF KEY MICROFAUNAS BY BRIAN MCGOWRAN Summary A planktonic foraminiferal fauna from below the Rivernook Member of the Dilwyn Formation in Victoria is important in earliest Tertiary correlations and age determinations in the Otway Basin. This fauna and the Rivernook fauna previously described are no younger than the Truncorotaloides aequa zone and its equivalents in tropical and Mediterranean sequences, and no older than the Truncorotaloides velascoensis zone. A review of recent studies indicates that both assemblages are older than Cuisian and that an Upper Paleocene (Ilerdian) age is still justified. There is some doubt about the ancestry of Pseudohastigerina, and the important Pseudohastigerina Datum seems to lie within the Upper Paleocene rather than at the Paleocene/Eocene boundary. LATE PALEOCENE IN THE OTWAY BASIN; BIOSTRATIGRAPHY AND AGE OF KEY MICROFAUNAS by Brian McGowran® SUMMARY A planktonic foraminiferal fama from below the Rivernook Member of the Dilwyn Formation in Victoria is important in earliest Tertiary correlations and age determinations in the Otway Basin, This fauna and the Rivornook fauna previously described are no younger than the Truncorvtaloides aequa zone and its equivalents in tropicul and Mediterranean sequences, and no older than the Truncorotulotdes velascoensis zone. A review of recent studies indicates that beth assemblages are older than Cuisian and that an Upper Palecene (Ierdian) age is stil justified. There is sone doubt about the ancestry of Pseudohastigerina, und the important Pseudohastigerina Datum seems toa lie within the Upper Palvocene rather than at the Paleacene/Eacene boundary. INTRODUCTION There are relatively few horizons in the earliest Tertiary of the Otway Basin to which an age can be given. Two of the marine ingressions in a paralic sequence were dated as Paleocene but only one, the Rivernook Member of the Dilwyn Formation, has a reasonably common and diverse planktonic fora- miniferal fauna (McGowran, 1965, 1968b, 1969). Recognition of “Middle Paleocene” and “Upper Paleocene” right across the Otway Basin (mostly in the sub-surface) depends heavily on these age determinations (Taylor, 1970a, b). Palynological biostratigraphy (Harris, 1965, 1970, pers. comm.) extends correlations far beyond the known occurrences of planktonic or benthonic foraminifera, into Tasmania to the south, Queensland to the north, and the Lake Eyre region to the northwest. The next horizon in the succession to which an age has heen given is regarded as early Middle Fucene (Ludbrook and Lindsay, 1969; MeGowran, Iarris and Lindsay, 1970), So long as planktonic foraminiferal assemblages are found only in sporadic ingressions (Taylor, 1967) they cannot be assumed to represent the total open ocean fauna of the region at the Hime, nar can species ranges (as shown by Ludbrook. 1967, fig. 2) be known meaningfully in the region, The open ocean fauna furthermore was marginal to the tropics where species diversities were highest and potential biostratigraphic refinement greatest. For all of these reasons new data on planktonic foraminifera have a pervading significance for local stratigraphy. This paper discusses an assemblage from just below the Rivernook Member of the Dilwyn Formation at Prince- town, Victoria, It is necessary ut the same time to discuss recent studics on Jate Paleocene chronostratigraphy so as to determine what can be meant hy ihe terms “Upper Paleocene” and. “Lower Eocene” and what is meant here, WANGERRIP GROUP In the Pebble Point to Princetown section in western Victoria ( Baker, 1953, Singleton, 1967) the Pebble Point Formation is overlain by the Dilwyn Formation (fig. 1). All samples studied palynologically by Harris (1965) included organic- walled microplankton, so that the environment was at least “marginal marine” throughout. Episodic ingressions (Taylor, 1967) are manifested by horizons * Geological Survey, South Australian Department of Mines, Trans. R. Soc, S. Aust. (1970). Vol. 94. bo B, McGOWRAN SECTION) LOCAL BIOSTRATIGRAPHY (2) Q@ Planorotalites cf. pseudomenardit 8 Planoratalites chapmani 8.8. : $ Truncorotaloides aequa {3,4} Se T Truncorotaloides aff. acuta (4) U Planorotalites chapmani ehrenhergi (3) PRINCETOWM MEMBER 'Trochocyathus Bed RIVERNOOK MEMBER "RIVERNOOK A> DILWYN FORMATION Dark carbonaceous and pyritic sandy clays. Approx. 600 feet exposed, PEBBLE POINT FORMATION Ferruginous grits, glhauconilic sandstones, silts, shales; Iwo unils wilh horizon of shelly fossils al base of upper. Approx, 80 feet. {Lower Cretaceous) (1) See Boker 1953, Singleton 1968. {2) Taylor zonules, in Singlelon 1968 ond. pers, comm. For palyno-biastrohgraphy, see Harris 1970, (3) Founas described by McGowran. 1965, (4) Planktonic lorominifero! assemblages discussed herein, $7577 B McGowran S.A, Dept, of Mines Fig. I. Outeropping section at Princetown, Victoria. with calcareous macrofaunas and microfaunas. The two foraminiferal assein- blages monographed (McGowran, 1965) come from the Pebble Point Formation and the Rivernook Member of the Dilwyn Formation. These and_ other fossiliferous horizons are good evidence for sporadically open-marine conditions, as shown briefly but clearly by Taylor (1967), Copiapite is common and appears to have derived from pyrite; the possible release of sulphuric acid would destroy calcareous tests (Taylor, 1965), However, the “marine horizons” appear to be real and not merely relics from an initially more complete fossil record because they aré widespread in the Otway Basin and can be recognised in borehole sections (Taylor, 1970a, b). The concept of periodic ingressions in a paralic regime (Taylor, 1967) would seem more accurate than a relatively simple transgressive-regressive cycle (Bock and Glenie, 1965, Glenic ct al., 1968), Tuylor’s biostratigraphic scheme, based on the section in the Latrobe bore al Princetown, was applied to the outcropping section (in Singleton, 1967) and is included here in an updated form (pers. comm. from: Mr, Taylor). Zonule Q is acknowledged by Tuylor as possibly Lower Eocene in age. ‘There is insufficient evidence at present to date Zonules Q and R; more material is needed particu- larly of the name fossils, LATE PALEOCENE 1N THE QTWAY BASIN » PRE-RIVERNOOK PLANKTONIC ASSEMBLACE Taylor's Zonule T (fig. 1) is based on a bed which he found below the Rivernook Member and desiymated informally as “Rivernook A”, Usually it is concealed by beach sand and remained unknown since the first studies on the stvtion by ©, 5, Wilkinson a ventury ago, Taylor found a planktonic assemblage in Rivernook A, not so rich in specimens as the Rivernook (McGowran, 1965) but excellendy preserved, The rock is a distinctively green, slightly indurated clay with silt, glauconite and mica. Prolonged search yielded excellent specimens although their number is low, The following were identified (specimen numbers included); generic nomen- lature is partly jfter McCowran (1968a) in this list and in the following discussion. Subbotina patagonica (Todd and Kniker) (10); S. aff. linaperta (Finlay) (1); Subbotina sp. (2); Planorotalites planoconica (Subbotina) (3); Psenie- hastigerina wilcoxensis (Cushman and Ponton) (11); Truncorotalpiiles Acarinine) esnaensis (LeRoy) (7); T. (Acarinina) cf, nitida (Martin) (5); runcorotaloides sp. (9): T. (Morozovella) wilcoxensis (Cushman and Pontou) (18); T, (Morozovella) aequa (Cushman and Renz) (3); T. (Morezovell[a) aff. acuta (Toulmin) (3); Chiloguembeling spp. (22) mecluding morphotypes crinita (Claessner), wilcoxensis (Cushman and Ponton), midiwayensis (Cush- mun), trinitatensis (Cushman and Renz). Brief taxonomic notes on this assemblage are included ut the end of the report; comments are based also on the collections from the Rivermnok Member described previously, Hivenook A contains, in addition to typical Rivernook clements, the important species Truncorotaloides aff. acule aud Psendohustigerina wileoxensis, one only of the latter having been recorded previously (as Globigerina pseudoiote Hornibrook) from the Riverwok Member, No namiofossils were found in a sample kindly prepared by Dr. H. Hekel (Geol. Surv. Queensland ), COMPARISON WITH THE BASHT MEMBER OF THE HATCHETICBER VORMATION IN ALABAMA Currently the Rivernook Member is correlated with the Truneerotalaides velascoensis zone of low latitudes (McGowran, 1968b, 1969), Previously attention was drawn to a considerable faunal similarity ta the Nanatalia Formation in Alabama (Planorotalites pseucdomenardii zone), Figure 2 includes all the bio- stratigraphic units mentioned io the following discussion. The planktonic assemblages. in the U.S, Gulf and Atlantic coastal sections are rich in acarininids, but all of those described by Loeblich and Tappan ( 1937}, Olsson (1960) and Nogan (1964) contain P. pseudomenardii and so belong in the zone of this name, None is known to ocenr in the Truneerotalvides veluscoensis zone which, indeed, has not been clearly recognised (Berggren, 1985), There is one possible exception in New Jersey (Olsson, 1969). The Bashi Member of the Hatchetigbee Formation in Alabama, separated from the Nana- falia by the Tuscahoma (without planktonics) has a rich acarininid fauna. The presence of Truncorotaloides subbotinae, T, wilcoxensis and Psendohastigerina wileoxensis has caused Berggren (1965, 1969b) to place the Bashi above the Truncorotaloides veluscoensis zone and to date: it as earliest Lower Eocene, A sample of Bashi from Ozark, Alabamn, has a rich planktonic fauna, It includes Psetdohastigerina wilcoxensis (Cushman and Ponton), acarininids matching the morphotypes Truncorotaloides (Acarinina) pseudotopilensis, 4 B, MeCOWRAN CALCAREOUS PLANKTONIC FORAMINIFERA NANNOPLANETON : 6 ites planuial " Globorutatia Globoratalia Truncoratalatdes : _ Nammulites planutates aragonensts ordponensis aragonensis Marthnusterites 4 a a _ ~ : tribrackiatos ~t Alveatine oblonga m7 Globorotalia Globorotalia Truncorotaloides gt { SS = rag ee ota = formosa formosa formosa | formosa formosa “sh { Nummp tites a i -aisbati Disevaster e ; Slonulatus 4 _ _ able an 4 -subnotinge- , finodosuy ~ ' se] Rab Ps. wiltoxenaia Globoretalia " & w ‘a Truncorulatoides =) Bhionentiaeds z|z sendphastigorina G. svubbotinae- aqua el m eC 4 u G. velascoensie Morthasterites =H DATUM Pa o contortus | “lole 7 os Globorotalia eee Truncorotalaides 3! = velascoensis WRISAGRE aes, velascuensis i. at = tscouster el - rte , we oe === HK Aa multirudiatus aS) ~ Zz e Ey a ~ — et z= , . : Heliolithas 3) St Globorotelia Globorotrlia Plonoratatlites riedeli rh pseudomenardit pseudumenardii paeudomenordii so <= & fs) (H Alles Bergucen (Pe, with Thanetan/fpresion boundary icken as Peleacene/Facere boundary 12] Alter Goll) 1957, 19ae (3) Alver Lutprbacher 1964, Cite el at, 1968; with generic nomas changed alles MeGawrar 1948, (4) Alrer Koy & Mohler 1947, 1989; see also Premol) Silver & lyterboche; 1986, Cita et of, 1948 (5) Position af sialelypes weterding to Hoy & Moklar 194% (Thenelina, Ypreuan), El Nagao 1969 [landeman], Lolafbache: 198%, Schoub PAP (lerdian, (6! Positier of lowest Cursron aummulitid nid alymalined zones, ales Huy & Mohler 19B?. Huy (6% (upper). Siebrand: 1965 leleibacher 1269 (middle), Gta ef al 6d Mower) (7! Solid gerows position of Preudehasiigermu Dulum elier Berygres T269¢ However Dalim could be a low 6: broken orraw (sre text) 70-76! B McGowran S.A. Dept of Mares Fig, 2. pigstratigeaphy and chrorostratigrapliy pertinent to correlation and age of Rivernook OTFZONS, esnaensis, soldadoensis, pentacamerata, gravelli and others, T. (Morozovella) wilcoxensis (Cushman aod Ponton), 7, aequa (Cushman and Renz), T. subhotinae (Morozova), T. pusilla laevigata Bolli, T. aff. acuta (Toulmin), fehilognemberns wilcoxensis (Cushman and Ponton), Ch. milwayensis (Cush- man) 4.1. The only significant absence, with respect to the Rivernook assemblages, is Chiloguembelina trinitatensis. The main components not fonnd in Rivernook or Rivernook A are some acarininid morphotypes and the keeled Truncorotaloides subbotinae-formosa group. The Rivernook and Riyernook A assemblages compare more closely with this assemnblage than with the assemblage from the Nanafalia illustrated by Locblich and Tappan (1957). CORRELATION AND AGE There are several problems inyolyed in the decision between a Paleocene and a Lower Eocene age for Rivernook A and the Rivernook Member. (1) Some important species are absent or poorly represented. Comparisons are best with other assemblages outside the tropical belt and the Bashi assem- hlages now seems closest. Correlations with hiostratigraphic sequences in e.g. the Caribbean (Bolli, 1957) or Mediterranean (Luterbacher, 1964; Cita et al. 1968) arc made rather difficult. That there is a climatic imprint on these mid- LATE PALEOCENE IN THE OLWAY BASIN 5 Jatitude faunas is indicated by the abundant acarininids (althwugh there is gond evidence that regressivencss has a conyerging cfiect), The absence of a particular species is less likely to mean that an assemblage lies outside its time range, so that negative evidence ean be more misleading than in the tropics, (2) Unless a correlation can be made directly with a classical stratotype of importance in time-stratigraphie classification (a first-order correlation; Reiss 1966) then the problem of age remains. It is not sufficient to correlate an horizon with cg. the “Truncorotaloides telascoensis zone”, no inaltter how good the correlation may be; palvnologists, basin-study compilers and all other warkers need the ave, e.g. “Upper Paleacene”™. This link in the chain of correlations back to classical sections involves other fossil groups. Recent studies on calcareous mannofossis are relevant here, as well as in indicating that the Bashi is some- what older than has been concluded on the planktonie foraminiferal evidence. As noted above, Berggyen lias suggested that the Bashi vorrelates with the “Glohboratalia rex" zone in Trinidad (Bolli, 1957), T. (M.) subbotinae (=rex) and T. (?M.) wilcoxensis being common te both and neither occurring in the Truncorotauloides velasceensis zane, Known “species” ranges show a pitttern of extinction and radiation in keeled globorataliids with the veluscnensis-acuta- ocelusa (stmeulatilis) group being replaced ly the newly radfating subbotinae- marginodentatau-formosa group (Bergeren, 1968). But there is a distinet overlap in the Trencorotaloides velascoensis and T. acqua zunes (Luterbacher, 1964, 1966, Cita ct al,, 1068), Berggren (1969 a, b) has noted that the last members of the velascoensis-ucuta group overlap with the first subbotinae. The association of T, aff. acuta with T, subbotinae-marginodentata in the Bashi suggests that this assemblage is no younger than this interval of overlap. Sinve T. aff. acuta occurs in Rivernook A the same criteria apply. The appar- eit absence of T. aff, acuta from the Rivernook Member could mean that it is slightly but significantly younger (by binstratigraphic analysis; obviously it is younger by superposition ), but iu a mid-latitude, paralic sequence this reasoning is dangerous. _ Tt is less cleay that the Bashi and Rivernook A ave no older than the “Globorotalia rex” zone. T, pusilla lneviyata in the Bashi compares exqellently with topotypes, and this species is regarded as distinctively Paleocene (¢\g- Berggren, 1968, fiz, 1), T. wileoxensis iy regarded generally us a post-Trunecoro- taloides velascoensis zone species (e.g. Berggren, 1968) but the aequa-teilcoxensis assemblage in the northern Caucasus (Alimarina, 1963) correlates in part with the Truncorotaloides velascoensiy zone ( Luterbacher, meth T. subbofinee aud T. formosa gracilis are recorded herein from the Bashi, but. their distinetness from 1. marginodentata and T, af. formose gracilis (Luuterbacher. 1964, 1966) is too tenuous io allow confident discrimination between the T. celascoensis and T- degua zones, The acarininid eluments typical of Lower Macene faunas aud found in the Bashi have much in common with similar assemblages in the Planoretalites poeudomenardi: sone, as noted ubove, and the complex was well established in the Truncoretaloides vélascoensis zone (c.g. Berggren, 1969), Acarining and Truncoretaloides s.s. scem to have persisted in higher latitudes beyond the level of extinction in the tropics (Bergyren, 1969b), There is evidence lor this preference for cooler waters in the Middle-Upper Paleocene range of this group. Acarminids are richer and more diverse in the U.S. Cult and Atlantic coastal region than in Trinidad. As a broad generalisation the Lower Eocene is relatively more regressive than the Upper Paleocene or the Middle Eocene throughout the world. This may have a climatic basis with acarininids becoming more charayter- istic of Jow-allitude scquenees by invasion at about the time tropical clements 1 B. McCOW BRAN (particularly the T. velascoensis group) were declining, A “marginal” assemblage vould have 2 Lower Eocene aspect yet be slightly older, and phyletio lincages In Acarinina are not known well cnough to exclude this possibility. Assemblages to which it upplies include the Bashi and Rivernook, and wlso the Gloherotalia subbotinae zoue in New Jersey (Olsson. 1964), It is concluded on foraminiferal evidence that the Rivernook A fauna is ne younger than the Bashi, and that the Bashi is no younger than the Truncore- teloides aequa zone (sense Luterbucher; see fy. 2) but could well be of the same ge as the T. velascoensis zone. Thus the toraminiferal evidence need not contradict nannofussil evidence for correlating the Bashi with the T. celascoensis zonc. Bramlelte agi Sullivan (1981) regarded the Bashi natineflora as transitional between their Discoaster multi- radiatus and D, tribrachiatus zones with greater similarity to the former ( Upper Paleocene), Tay (1964) placed the Bashi tentatively near the top of the Marthasterites contortus sone (which is shown to fill a gap between the Bramlette and Sullivan zones; Hay et-al., 1967, fig. 2) and slightly ahove the “G/oborolalia rex” zone in Trinidad, More recently (Hay and Mohler, 1967, Hay et al., 1967) the Bashi is placed in the Discoaster multiradiatizs zone, which includes alse the Truncorotalvides velascoensis zone in Trinidad and northern Italy (but see Cita vt wl, 19868), and this zone and the Planorotalites psendomenlardit zone in the Velasco Shale in Mexico, Indeed, on the correlation of zones presented by Hay and Mohler (1969) the Bashi would fall low in the T. velasenensls zone, The “Gleborotalia rex” zone in Trinidad was said to have a nannofossil assemblage characteristic of the upper purt of the Marshasterites contartus zone. The Paleocene/Eocene boundury was placed at the top of the Truncare- tulvides celascoensis zone ( Bolli, 1957, 1966), Berggren (1969 a-c) has moved it slightly higher hecause of the important overlap noted abnve, to within subzone P6a (subbotinae-velascoensis) (fig. 2), This is regarded as being also the Thanegian/Ypresian Sttgze boundary, but the evidence for correlating stratotypes of these or other stages (Spamacian, Landenian) with planktonic foraminiferal zones is very weak, and the evidence from nannoHoras shows a gap. Sequeners in north-west Europe pertinent to: chronostratigraphie classification have, at best restricted cooler-water and/or regressional assemblages dominated by acarininids and poor or lacking in significant keeled globorotaliids (Berggren, 1960, 1969b, Bronnimann et al., 1968; Moorkens, 1968; E1-Nagyer, 1969), Nonc of the species identified and diseussed by Moorkens from the Ypresian demonstrate that this stage is younger than the Thanctian (as it clearly is); several, Mdeed, oceur as low xs the Plarvretulites psendomenardii zone, The nannotlaras indicate that the type Thanetiai [les in the Heliolithus riedeli zone and that the type Ypresian is as low us the Discoaster binodosus sone (May aud Mohler, 1967; Bignot and Lezard, 1969), In the Paris Basin, the nummulitid and alveolinid faunas of the Cuisian Stuge can be corelated with faunas in the Mediterrancan region and integratecl wath evidence from planktonic microfossils. The Paleocene/Eocene boundary has been drawn xt the base of the Cuisian Stage, at the base of the parallel zones of Alveolina oblonga and Nummuilites planulatus (ITottinger and Schaub, 1960; Hottinger, Lehmann and Schaub, 1964), The Lerdian stave of Mottinger and Schaub then is the highest chronostratigraphie unit in the Paleocene. With respect to the biostratigraphic systems based on planktonic microfossils, this boundary has been placed at three closely spaced but rather distinct levels (fiz, 2). The Niammeulites planulatus zone has been identified in the Schlierenflysch fn Switzer- land within the Marthasterites. tribrachiatus zone (Hay and Mahler, 1987. and vels, therein) and within its middle part ( Hay, 1969), The latter zone is relatively LAT PALEOCENE IN THE OTWAY BASIN 7 large (ITay and Mohler, 1969) and the base of the Cuisian could be as high as the Truncerotaloldes aragonensis zone. Woweyer, Bignot and Le Calvez (1964) have recorded T, subhotinadg-marginodentata from the Cuisian (see alsa Brénni- mann et al. 1968) indicating that the Cuisian should include at least part of the Truncorotaloides formosa zone; this is consistent with the range of the Derdian according to Hillebrandt (4965) and Luterbacher (1969). Finally, Schaub (in Cita et al. 1968) has identified the basal Culsian at an horizon within ihe Dis- coaster hinadostus zone, at about the top of the Truncorotaloides aequa zone. Clearly, there are still problems in relating liostratigraphic systems to a consistent chronostratigraphic framework. In chronostratigraphic enquiry there must be, ultinately, a balance between historical weight and practical value (i.e. circumglobal recognition) and a formal decision as to the best position for the boundary between two stages. Tt would seem at present that, of the alternatives for a Paleovene/Eocence boundary, the Nerdian/Cuisian boundary is the most useful and promising for biostratigraphic correlation, the [erdian fulfilling strati- graphie requirements (Schaub, 1965, 1969; Luterbacher, 1960). The Truncare- laloides aequa zone is iti the Nerdian. This means that the Bashi Marl in Alabama and the Rivernook atid Rivernook A assemblages in Victoria are Upper Paleocene in age. THE PSEUDOHASTIGERINA DATUM The current trend in Tertiary biostratigraphy is somewhat away from the use of zones, defmed in the various ways listed in endes and texts. The differences netween mid-latitudes and the tropics, and between nearshore and deep-sea assemblages. account for much of the confusion among, existing biostratigraphic systems and the typological, agnostic (“nhjective’) approach to morphotype recognition and definition accounts for some more, Greater attention is being vnid to “datum lines” (or “surfaces”) particularly as marked by the emergence of a species from a known ancestor in a well-documented phyletic series (either successional shift in observable morphological range or bifurcation, speciation). Total-range zones are the best if the index species hus a short range in tine (“life”) but the lower boundary is the better in any case bevause il represents a unique event in evolution, whereas the upper boundary is based on extinelion which is a “plane” only until demonstrated otherwise. (In practice, some extinctions such as the mass extinction of planktonic species at the top af the Maastrichtian have excellent correlational value, ) One such datum is represented by the first appearance of Pseudohastigerina wilcoxensis at or close to the Paleoeenc/Eocene boundary. It was considervd to coincide with the extinction of Truncorotaloides veluscoensis (Berggren, 1964). und still marks the base of the Eocene even though the ranges of vertain other species are changed slightly (Berggren, 1969¢) (fiz, 2), The value of the datum lies further in the occurrence of Pseuclohastizerina at latitudes and. in faeies where important species are not found, and also in that the immediate ancestry has heen inferred (Herggren et al., 1967), In the folluwing discussion doubt is vast on the ancestry and on the time of the first appearance. According to Berggren et al. (1967) Plenorotalites ehapmani (Purr) is the immediate ancestor of Pseudohastigerina iwilcerensis. The latter species includes distinctly trachospiral as well as pseudoplunispiral forms (nates on species, below). Occasional specimens with slightly more compressed chambers than usual (Berggren et al. 1987, text—fig, 2d-f) are the only published, visual evidence of ancestry in P. chapmani, although Berggeen (1964-1964c) has recorded the range of P. chapmani as overlapping slightly with P. wilcoxensis with some intergradalion (e.g. in the Bashi). bs B. McCOWRAN This raises the question of the identity and morphological range af Planore- talites chapmani. In the original material (McGowran, 1964) this species has a compressed test with rather acute periphery, giving arrowhead-shaped chambers in profile, and it has an imperforate marginal band (McGowran, 1968a, pl. 4, fig, 15, 16), Globeretalja troelseni Loeblich aml Tappan is a janior synonym und this compressed form appears not to range above the Planorotalites pseudo- menardtt zone (Berggret 1964). “G. elongata Glaessner” wuett. is also synony- mons with P. champani, at least in part (MeGowran, 1964). Recently figured sneeiniens of P. chapmani from the Planorotalites pseudomenardii zone ( Berggren ct al, 1967, pl. 1) agree with typical P, chapmani except that a fully perforate margin is shown (drawing only. not photograph or thin section) and the speci- mens are small, There seem to be no convincing records published to support the contention that P. chépmani ranges well above the P. pxéudomenardté ore, In Western Australia P. chapman is replaced in the P. simplex zone (correlated with the Truncaretulsides veluscoensis zone; McGowran, L968b) by a closely related but distinct species identified as FPlanorotalites ofriples Hague (MeGowran, 19684, pl, 4, fg, 19-20, 22), P. sinzplex occurs at the same level m West Pakistan (Haque, 1956; see McGowran. 1968b), and in Austria (“G, elongata” of Wiltebrandt, 1962). illebrandt (1965) reeurds 2. simplex trom the Flanoretalites pseudomenardii and Sruncoretaloides velascoensis zones in Spain. Althuwzh Hay (1960) records “Globoretalia elongata Glacssner” from the Truncorataloides velascoensis zone in Mexico, Bergyren et al. note the similarity of a figured specimen (Loeblich and Tappan, 1956. pl. 63. fig. 2) ta Clabano- maline simplex; it is not a typical P. chapment. Typical P. stinplex appear be range down to within Planorotalites pseudomenardii zone but, particularly on the Western Australian evidence, P. simplex appears to be distinct from avd mostly snecessivual to P. chanypani rather than a “morphological variant” of the latter as suggested by Berggren ct al. Very small specimens in the Bashi are wot convineing evidence of a P. champani—P. teilcoxensis phyletic transition, which remains inferential, Specimens identified us Cleborotalia imitata Subbotina (see esperially Loeblich and Tappan. 1937. McGowran, 1965) show very close siri- lnrity to Pseudvhastigerina of the more trochospical, asymmetrical type, and suggest this species as & likely ancestor. A similarity in wall thickness increases this shidlarity, in contrast ta P. chapmani { MecGowran, 196Sa, pl. 4), However, in the early Middle Eocene of South Australia assomblages of P, wilcovensis inelude individuals, seemingly intergrading with the typical form, which would fit quite easily in a Paleocene population of P. imitata. Cordey et al. (1970). however, maintain the alternative view Hat FP. chapmani is the aueestor at Pseudohastigerina, P.. wileoxénsis is well known in the Tytincorofateides aegua zone and its equivalents (Berggren et al. 1967; Berggren, 1969a-c, Reckmain et ul, 1969; Hillebrandt, 1965). A few poor specimens have been found in a sample from the “Cloborotalia rex” zone in Trinidad. Reasons given ubove tur making the Terdian/ Cuisian boundary the Paleacenc/Eocenc boundary mean that these occurrences are of Paleocene rather than Eocene age. Nannofossil evidence for corvelating the Rashi with the Truncorotaloides velasooensis zone indicates a shill lower first occurrence. There is other evidence tor this. Globanomalina ovalis Haque s.s. is x poorly Known taxon (see especially Berggren ct al.. 1967) but must he very close to Psendohastiverina, yet it is associated near the base of its range (Salt Rusge, Pakistan) with Planorotalttes pseudomenardii (see MeGowran, 19fSb for discussion on Haque, 1956). Latif (1964) records “Hastigerine pseudoiota (Hornibrook)” from probable Upper Paleocene, also in Pakistan’ (McCowrats, LIGSb), “Globorotalia (Lurboratelia) cf. pseudoiota” was found associated with LATE. PALROCENE IN ‘THE OTWAY BASIN 9 Planorotalites pseudomenardii in the equatorial Atlantic (Cifelli et af., 1968), Chaiier and Lahsen (1968. 196%) recorded a planktonic ussemblage from the lower Agua Fresea Formation, southern Chile, with Globanomalina pesudoiota, G, compressa (Plummer) and “G. membranacea (Ehrenberg )" er nutes en spews, below). This assemblage bas u Paleocene aspect. Ne Subbotina patugonica were reported whercas this species is characteristic of the Agua Fresea (Ilerm, 1966) and associated with Pseudohastiverina wilcoxensiy, indicut- ing a Lower Eocene age for the upper part (Berggren, 1969b)}. Thus, neguative evidence also indivates a Paleocene age for Charrier and Lahsen’s assemblage. On the other hand, the assoeiated nannofossils have an earhy Eocene aspect, and the presence of Discouster tribrachiatus suggests an age of no older than D. binedosus zone. The first occurrence of Pseudohastigerina wilnoxensis in New Zealand is one of Jenkins’ inain datum planes (Jenkins, 1966) but its actual position is difficult to evaluate from published ranges (Jenkins, 1965). ‘The Globanomaling wilcoxensis zone was correlated with the Truncorotaloides “rex”- 1. formosa interval in Trinidad, However, the range of the T, velascoensis group appears to be more restricted in New Zealand than Jenkins allows because P. pseudomenardii extends above it; Uhus there is vo evidence for a Truncorotaloides eelascosnsis zone, Either important species are restricted or missing for clijnatic reasons, or part of the section is missing, That is, the problems appear to be the sume as in Victoria, Tn conclusion, it can be said that there is still room for legitimate doubt about the immediate ancestry of Pseudolastigerina, although there is no doubt that it arase from the carly Tertiary genus Planorotalites. Further studies on its phylo- zeny and classification are needed. It sectns, however, to have emerged during the Upper Paleocene and below the top of the Truncoretaloides velascoensis 7one, NOTES ON SPECIES AND MORPHOTYPES Subbotina putagonica (Todd and Kniker): agrees well with original description and recently identified Lower Eocene forms (Berggren, 1969b) uxcept that the aperture can be even higher. Subbotina aff. linaperta Rial): Most Rivernoak specimens are not so compressed laterally as specimens of S, Iimaperte from the Bortonian of New Zealand and the refigured holotype from the same level (Hornibrook, 19582); this comment applies to most pre-Middle Encene records of S. linaperta. S. trivialis (Subbotina) may be added to the list of morphotypes given previously. Planorotalites planoconica (Subbotina): probably a better name bis most of Rivernook P. chapmant (Parr). Close ta but distinct from Pebble Point P- chapmant compared with ehrenberyi (Bolli) or haunsbergensis (Gulrbandt). The latter is closer to, but seemingly distinct sample-wise from, P. australiformis (Jenkins) from the Middle Eocene of South Australia. [t is also probably identical with “Globorotalia membranacea (Ehrenberg)” of Charrier aud Lahsen ( 1968 ). Since P, australiformis is recorded from tha Upper Paleocene to early Middle Kocene in New Zealand (Jenkins, 1965) the significance of the Pebble Point species as a Middle Paleocene indicator is reduced. Whercas Planorntalites chapmani ehrenbergi/haunshergensis occupies « fairly clearcut position in tropical sections (Middle Paleocene; ancestor of FP pseudomenardii), and in New Jersey (Olsson, 1969), 0 lineage extends to the Middle Eocene in mid-latitudes and needs detailed study. Pseudohastigerina wileoxensis (Cushman and Pontoon); agrees with Globi- fering pseucoiota Hornibrook (1955 a, b), Aperture and coiling show strong asymmetry (see also Hornibrook, le.; Latiff, 1964; Chartier and Lahsen, 1968, kee) B. McGOWRAN Fig. 3. oO G-l 0:2 O-3 o-4 eH, Planktonic foraminifera from the Rivernook A horizon. Each specimen shown in three views; 1. Truncorotaloides (Morozovella) aff. acuta (Toulmin). 2, 3, Pseudohastigerina wilcoxensis (Cushman & Ponton) of the asymmetrical, pseudoiota type. 4, 7, Planorotalites planoconica (Subbotina). 5, Subbotina patagonica (Todd & Kniker). 6, T'runcorotaloides (M.) wilcoxensis {Cushman & Ponton). 8, Truncoro- talaides (Acarinina) esnaensis { Leroy). 9, Truncorotaloides (M.) aequa (Cushman & Renz), LATE PALEOCENE IN THE OTWAY BASIN 11 and there are none of the almost planispiral variants of P. wileoxensis figured from New Zealand and New Jerscy assemblages (Berggren et al., 1967) and observed together with the others in topotype material (Bashi Member of Hatchetighee, Alabama). This primitive aspect persists into the early Middle Eacens in South Australia, Berggren ct al. suggested that C. psendoiota should be placed in synonymy with P. wilcoxensis, but further study (Cordey et al., 1970) Indicated that it may be better placed in P, sharkriverensis Berggren and Olsson, The early members of the lineage are rather problematical, especially in Australia as acknowledged by Cordey et al,. and the name P. wilcoxensis is tentatively maintained here pending further clarification. Incidentally, these authors’ discussion of my (19681, g 1) “view on the phylogeny of the pseudohastigerinids” gues well beyond the original intention, the “view” was merely to use sufficient morphotypes to indicate an evolutionary trend for the purposes of genus-group and family-group classification, Truncoretuloides (Acar{nina): acarininids are: notoriously variable and intergradationa! in the Upper Paleocene and Lower Eoverie (see, however, uscful discussion of synonymy by Berggren, 1968). T. (A,) esngensis and T. (A.) ef, nitida in Rivernook A may be distinct, but much larger assemblages in Rivernook proper range from pentacameratd Subbotina or soldadoensis Bronnimann through a “central” group of esnaensis, intermedia Subhotina, ete., to triplex Subbotina, pseudetopilensis Subbotina, etc. Tightly coiled pre-Middle Eocene forms referred by several authors to primifiva Finlay can mostly be distinguished from this species, : Truncorotaloides sp: small, five-chambered, rounded (cf. pentacamerata Subbotina) or truncate and Hattened spirally (cf, apanthesma Loeblich and ‘Tappan ). Occurs in Riyernook and also Bashi Truncorotalaides (M.) aequa aud T. (M.) wilcoxensis: lumped previously, but specimens in Rivernook praper compare very well with topotvpes of both Inrms. Same in Rivernook A, T. (M_) aff. acuta: strongly truncate, highly conical chambers, angular and slightly keeled margin, umbilical shoulders with slight thickening. Compares well with topotypes of T. aeufa but lacks strong thickening of shoulders scen in largest and in those closest to velascoensis (Cushman) (see e.g, Loeblich and Tappan, 1957). Not found in Rivernook praper but uceurs in Bashi, Very similar to specimens in Planorotalites pseudomenardii cone in south India whieh in turn provide link with 7. conieotruncata (Subbotina). Chiloguembelina spp.; morphotypes listed appear to be matched in Rivernonk A und Rivernook proper (see Beckman, 1957), but consistent separation into coherent taxa is rather doubtful even with excellent material, CONCLUSIONS (1) The Riyernook A assemblage is similar to the Rivernook assemblage except that there are fewer specimens. Truncorotaloides aff, acuta is present and Pseudehastigerina wilcoxensis is relatively well represented, (2) Both assemblages are characteristic of ucarininid-rich, mid-latitude faunas in the curly Tertiary, and the similarity with the Bashi Member of the Hatchetigbee Formation in Alabama is particularly striking, (3) Reeeut studies of calcareous nannofossils indicate that the Bashi correlates with the planktonic foraminiferal zone of Truncorotaloides celascaensis rather than slightly higher. It is concluded on foraminiferal evidence also that the Hashi and Rivernook assemblages nced be uo younger, but that a range in 12 B. MeGOWRAN possible correlation including the Truncorotaloides velascoensis zone and (lower) Truncorolaloides aequa zone is the most precise presently justified. (4) The Merdian/Cuisian boundary seems to be the best position for the Paleocene/Eocenc boundary. Both of the assemblages from the Dilwyn Formation ure Nerdian and therefore Upper Paleocene in age. (5) ‘The evolution of Pseudohastigerina wilcoxensis from Planorotalites chapmani has not been demanstrated completely and remains inferential, Planorotalites imitata is a possible alternative ancestor, The Pseudohastigerina Datum lies within the Upper Paleocene, not at the Paleocene/Eocene boundary. It could be close to the hase of the Herdian, ACKNOWLEDGMENTS 1 am indebted to several colleagues. Mr. D. J. Taylor (Sydney) diseovered the Rivernook A horizon, provided the sample, encouruged this study and com- mented on an carly dratt. Prof. M. F. Gluessner (Adelaide) Jent the Bashi sample collected by Prof, L. D. Tonlmin and himself at Ozark, Alabania. Dr. W. A, Berggren (Woods Hole), Dr. H, Luterbacher (Bordeaux) and Prof. L. D. Toulmin (Tallahassee) provided comparative material. The paper is published with the permission of the Director, Sonth Australian Department of Mines. REFERENCES Avisranica, V, P,.. 1963. 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A., 1964, Paleocenc-Lower Eocene biostratigraphy of Liixor and nearby western Desert, Petrol, Expl. Soc. Libya, 6 Annual Field Conf,: (49-176, pla, t, 2, Aynsterdam. Brenecnen, W, A. 1965, Some problems of Paleocene-Lower Eocene: planktonic foraminilersd vorrelutions. Micropwleontology 11; 278-300, pl. 1. Brrconen, W. A, 1968, Phylogenctic. and taxonomie problems of seme Tertiary planktonic foraminiferal lineages, Tulane stad, Geol, 6: 1-22, Berccars, W, A... 19690, Biostratigranhy and Binite toraminiferal zonatian of the Tertiary system of the Sirte Basin of Libya, north Alrica. Pree, tsi, Intermat, Cont, Planktanic Mierotossils, Geseva 1967, Brémuimann, P. and Renz, UI. 1, ds. 1: 104-120. Beracren, W. A,, 1969b, Paleogene binstratigraphy and planktonic foraninitera of narthory Europe. Ibid, 1; 121-160, Bereonen, W. A, 1969c, Rates of evolution in some Cenozvice planktonie: foraminiferns. Micra paleontolopy 15: 351-365. Theiiannws, W. A. Orssox, Ro K. and Rueyaena. KR. A. L967. Origin and developiment of the foraminiferal aenus Psendohastigerina Banner and Blow, 1959. Mieropaleontology 18: 265-284. Rieaut, G. and Le Caryvrz, T., 1969, Contribution A l'étude des toraminiféres planctoninques de ’'Bocéne dit Bassin de Paris, Proe, Let lvternal, Cont. Flanktonic Microfossils, Geneva, 1967, Brénnimann, P. and Renz, 17. 2, eds. Ls 161-186. Bicwor, G. and Lezaty, L., 1969, Suv Ia présence de Marthasterites tribrachiotus cays VYprésien dy bassin anglo-franco-belge, Revue Micropaléont, 12; Lip-122. Buck, PoE. und Grnie, 2. C,, 1965, Late Cretaceous and Tertiary depositional cycles in south-western Vietoria. Proe. R. Soc. Viet. 79: 153-163, Bora, WM, 1957, The genera Globigerina and Globorotalia in the Paleucene-Laswer Eouerie Lizard Springs Iformation of “trinidad, BAW.T. Bill, U.S. natn. Mus, 215: 61-82, pls. 15-20. LATE PALEOCENE, IN THE OTWAY BASIN 15 Bure, H. M., 1986, Zonation of Cretaceous tv Pliocene marine sediments based on planktonic foraminifera: Bol. Inf. Asoc. Venez. Geol. Min. Petrol, 9 (4); 3-32. Baadmerrm. M,N, and Sucutvan, F. R., 1961, Coceolithophorids and related nannoplankton of the Tertiary in California. Micropaleontology 7: 129-188. BRONNIMANN, P., Curry, D., Pomeron,.C,, and Szots, E., 1968. Cantribulion § Ta connaissance des Foraminiféres planctoniques de ['Eoutme (incluant le Paléocéne) du Bassin Angla- Franco-Belge, Mém, Bur, Reeh, Géol. Min. Parts 58: 101-108. . Ceangrer, Re and Larsen, A. 1968. Contribution & létade de la lintite Crétacé-Tertisire dans ly Provinee cde Magellan, extréme sud du Chili Revue Micropaléont, 1b: 111-120, Citaniien, TR. and Larsen, A. (969. Stratigraphy of Ivte Cretaceous-early Eavene, Seno Skyring-Strait ol Magellan area, Magellanes Provines. Chile, Bull, Am, Ass, Petrol) Geel, 53: 568-590. Cyeecuy, i, Biow, W. H. and Merson. W. G,, 1968, Paleogene sediment From w Fracture zone of the Mid-Atlantic Ridge, J. Mar. Res, 26: 105-109. Orra, M. B., Premou-Sinva. L, Touxranxisr, M, Bowls, H. M,. Lurensacnen, H. P., Mouien, H. P. and Sonava, H, 1968. Le Paléacéne de Poderno d’Adda. Mém, Bur, Rech, Géol, Min. Paris 58: 611-427- Coxwry, W. G., Beaconny, W. A. and Onesen, RK. 1970. Phylogenetic trends in the plank- tonie forantiniferal genus Pyeudohastiyering Banner and Blow 1959, Micropaleontology 16: 235-242, Eu-Nagcar, Z, B., 1969. New -suggestiony for the division and correlation of Paleocene strata by the ne of planktomie foraminitens. Proc. Ist Internat, Conf, Phiuktoni¢ Micrufossils, Geneva, 1967, Broonimam, 2 and Renz, 1. A, Eds. 2: 182-207, Cannie, B.C, SoaorteLy, J.C. and Wann, W-'T., 1968, Tertiary sea levels in Australia and New Zealund. Palacogeog.,. Palacoclim,, Palaeoevol. S: 141-188. ITagun, A. F. My 1956, The foraminifera of the Ranikot and the Laki of the Namma!l Garge, Salt Ranive, Paleont, Pakist. L: 1-300. Jiamus, W. K., 1965. Basal ‘Tertiary nicrofloras frou the Princetown area, Victoria, Artstralia. Palavontopraphiea 115 (B): 75-106. pls, 24-29. Hanis, W. K. 1970. Tertiary stratigraphic palynalogy, Otway Basin, Ch, 4 in The Otway Basin in south-east Australia, Spec. Bull, geal, Surys. 5. Aust. Viet. (in press). Hay, W. W., 1960, The Gretaceons-Tertiary boundary m the Tampico Enibayment, Mexioo. Proc, 2st Int; Geol. Conur., Sec. 3: 70-77. Mav, W. W,. 1964, Utilisation steatigraphique des Discousterides pour la zonatian du Paléo- céne et !Eocéne inférienr, Mém. Bur. Géol.. Min. Paris 28: 8435-889, Hay, W. W., 1969, On definining boundaries between the Paleoeaue, Kocene add Oligocene, Thid. 69: 197-200, ; Hay, W. W. and Mouens, I. P., 1967, Caleareous nannoplankton fren early Tertiary rouks at Pont Labau, France. and Paleocene-eurly Eocene correlutions. J. Paleant. 41: 1505-1541. pls. 196-206. Har, W. W. and Morcen, H. P., 1964. Paleacene Eocene: calcareous nannoplankton ane ligh- resolution biostraiigraphy, Prov. Ist luterual, Conf. Plinktonic Microfossils, Geneva 1987, Brénniniann, P, ancl Renz. 1. H., Eds, 25 250-253. Hav, W. W., Motiter, H. V., Roru, Po, Scum, BR. Re and Bounakaux, J. M., LY6T. Jalearcous nannoplankton zonation of the Cenozoie of the Gull Gowl and Caribbean- potion area and transoceanic correlation. Trans. Gulf Cst. Ass. Geol. Sov. 17; 428-480, 3 pls. Heam, D., 1966, Micropaleontological aspects of the Magellanese: Geosyncline, sonthernmust Chile, South America. Proc. Sud W. Afr, micropalcont. Coll, (Thadan, 1965), Lieitlen, KE. J. Brilly 72-86. Huwearanor, A, vos, J962, Das Paleoziin und seine Foraminiferenfuxna im Becken von Reichenhall und Salzburg (Nordliche Kallulpen), Bayer, Akad. Wiss. Math,-nalurwiss. Kl, Abh, N.F, L08; 1-182, 15: pls. Thitimsnanpr, A. yor, 1965, Foraminiteren-Stratigraphle lin Alltertide vay Zimaya ( Proving Guipdzcoa, N, W, Spanien) und cin Verwleich mit auderen Tethys-Gebieten. Uhul, 123; 1-62 Horniprpock, N, be B., 1958a, New Zealand Upper Cretaceous and Tertiary foraminiferal yon's and some overseas correlations, Micropaleoutology 4: 25-38. Honnwrsnoox, N. pe B., 1958b. New Zealand foraminifera, Key species in stratigraply—No. 6 N.Z. J. Geol. Geophys. 1; 653-676. HMortincer, L, and Sonavn, H., 1960. Zur Stufeneintellune des Paleocacns und des Eneaeus. Einfithring des Uerdien und des Biarritzien. Eloy. weol, Melv. 53: 454-579, Hownncer, L,, Leaarann, B. and Scuave, H.. 1964. Dannérs actnelles snr la biostraligrtphic da Nunimulitique Mediterranéen. Mém. Bur. Hech, Géal, Min. Paris 28; 611-652, AGE DETERMINATION OF POUCH YOUNG AND JUVENILE KANGAROO ISLAND WALLABIES. BY CLARE R. MURPHY* AND JANCE R. SMITH* Summary Repeated measurement of head, leg and foot lengths were made during the development of young Kangaroo Island wallabies (Protemnodon eugenii) of known age. The measurements were used to construct age regressions. Size was fairly closely correlated with age until the young were 320 days old but thereafter it had little value for age determination. The reliability of using the regressions to determine the age of young wallabies has been tested by using them to estimate the age of 14 young of known age. The largest error between the estimated and actual age of the young was about 5%. Growth proportions of captive and field-reared young were compared and these were found to be similar until the young were about 350 days old. AGE DETERMINATION OF POUCH YOUNG AND JUVENILE KANGAROO ISLAND WALLABIES. by Cyane R. Murruy® ano Janice R. Suri? SUMMARY Repeated measurement of head, leg and foot lengths were made during the development of young Kangarou Island wallabies (Protemnodon eugenit) of known age. The measurements were used to constnict age regressions. Size was fairly closely correlated with age until the young were 320 days ald but thereafter it had little value for age determination. The reliability of using the regressions to determine the age of young wallabies has beun tested by using them to estimate the age of 14 young of known age. The largest error between the estimated and avtual age of the young was about 5%, Growth proportions of eaptive and field-reared youmg were compared andl these were found to be similar until the young were about 350 days old. INTRODUCTION Several studies made on the growth rate of marsupial young in the pouch have shown that the age ef young captured in the field can be accurately estimated by compuring their body measurements with those of captive young of known age (Shicld and Woolley, 1961; Sadleir, 1963, Sharman, Frith and Calaby, 1964), A study on the ecology of the Kangaroo Island wallaby (Protemnadon éugenit Desmarest) living in Flinders Chase, Kangaroo Island, required a method for accurately determining the age of pouch young and juvenile wallabies cap- tured in the field (Andrewartha and Barker, 1969). For this reason the growth of captive pouch young was studied and the reliability of using these measurements to determine the age of captive pouch young wus assessed, The present study also examines the validity of applying these imcasurements to fixing the age of young Kangaroo Island wallabies in the field. METHODS During this study a domestic colony of Kangaroo Island wallabies was niiintained in the Zoology Department, University of Adelaide, Details of animal husbandry are reported by Murphy (1970), During the breeding season (January-July), the pouch of each female was examined daily until the birth of a young; the young were subsequently measured each week until they were about one year old, Yearlings were measured once a formight because of their slow growth rate. A total of 16 young were observed throughout the study but at any one time only seven young, were measured. The lengths of the head, left foot and left leg were measured in the manner indicated by Sharman ct al, (1964). Vernier callipers were used to neasure head and foot lengths of all the animals and the leg length of pouch young, while a steel tupe measure was used to measure leg lengths of older animals. Fourteen of the young were weighed at intervals throughout the study; most of them were weighed several times, They were weighted on a variety of balances since no one balance covered the range of their weights, Until they were 100 days old, the young were removed from the pouch and measured while still attached to the teat. Older pouch young were detached from the teat and measured, During measurement of the yormg, the rnothers were restrained in jute sacks: no young were lost through the handling of the mothers. °“Taology Department, The University of Adelaide, Trans. R. Soc. §, Aust. (1970), Vol. 94. 16 C. R. MURPHY anp J, R. SMITH Juveniles and yearlings were restrained in jute sacks while their body parts were being measured. Both operators measured the young every time and the average of the two estimates was taken to the nearest 0-1 mm. with the callipers and to the nearest 0-5 mm, with the tape measure. Weights were recorded to the nearest 0-1 ¢, Before regressions calculated for young wallabies reared in the laboratory can be used to age young in the field, it is necessary to establish that wallabies in the laboratory and the field have the same growth proportions, For this purpose 87 young wallabies were collected at different times of the year in Flinders Chase, Kangaroo Island and were measured and weighed by one of us (C.M.) in the same way as the laboratory-reared animals. RESULTS The measurements made on laboratory-reared young aged 3-450 days are presented as regressions of age versus head length, leg length and foot length (Figures 1, 2 and 3). dk *FEMALES Sil “MALES 7 2 age Be gph SB See = n vs gronone OS EMEP pobre wear Bee te ; SiSaage ae oF seragey eee = 6 i we kee Py: ssi 4 a ot a3 2g x2 en 1h a a ai ats a a or re | fy) 50 100 150 200 250 300 350 400 450 AGE (DAYS) Fig. 1. Regression of head length on aye for Kangaroo Island wallabies aged 3-450 days. “FEMALES 20 *MALES . att : LEG LENGT a 50 100 150. 200° 350 300 350 400 450 AGE (DAYS) Fig. 2, Regression of leg length on age for Kangaroo Island wallabies aged 3-450 days. AGE DETERMINATION OF KANGAROO ISLAND WALLABIES: 17 | “FEMALES is| "MALES : 14 es aa v ot PNSSES wee PU EE? ~ 104 cian se FOOT LENGTH wo VoronwAaoe e & a oe 1. a} 200 250 300 350 400 450) AGE (DAYS) Fig. 8. Regression of foot length on age for Kangaroo Island wallabies aged 3-450 days. pon 150 The regressions show no marked differences in the growth rate of young male and female wallabies up until the time they leave the pouch permanently at 245-270 days. From this time the regressions for male and female young begin to diverge, the males being on average larger than the females, Inspection of the thrce regressions shows a considerable scatter of points, much of which is due to the difficulty of making accurate measurcments on the young. An age estimation based on a single body measurement could therefore be subject to a greater error than an estimation bascd on all three body measurements, A series of measurements were also made on 14 young of known age which were not included in the regressions. Table 1 shows the measurements of these young, together with their ages as estimated from the three regressions, and their actual ages. TABLE I Measurements of young Kangaroo Island wallabies of known age, not inclided in the vrowth regressions, and the ages of these young estimated from the regressions. Reference Lengths (em.)* Estimated Actual Days Number Age (Days) f (Days) and. Sux Head Leg Foot 74(?) 0-87 (4) 0-41 (5) 0-33 (5) 5 3 lz 1-12 (12) 0-61 (12) O41 (8) il 10 29 1-22 (15) 0-69 (14) 0-55 (14) ld 16 34 (?) 1-29 (17) O78 (17) a: 17 17 144 1:67 (27) 1-15 (26) 0-84 (27) 27 26 679 2-00 (86) 1-42 (34) 1:08 (35) 3a 36 595 4 2-78 (58) 2°45 (57) 1-84 (59) 58 59 14P g 3:77 (92) 4-03 (91) 3-18 (95) 93 g4 §49 4-35(115) 5+31( 116) 4:15(114) 115 11] 779 4-42(118) 5-50( 120) 4-34(118) 119 123 594 9 4-50( 121) 5:83( 124) 4.90(126) 124 129 769 5-45(162) 8:74(164) 7-55( 166) 164 163 949 5-°79( 174) 9-76( 176) 8-47(177) 176 185 SE 4 6-45( 199) 11-80( 197) 10-74(203) 200 197 * Estimated ayes from each measurement are in parentheses, ¢ Based on average af ages estimated from each measurement. EYES TEere and FOOD FUR STANDING ERECT POUCH LIFE HEAG LENGTH LEG LENGTH Foor LENGTH 18 C. R. MURPHY anp J, KR. SMITH It can be seen that the largest actual error in age estimations for any of the young was nine days when the estimate was made from all measurements (young no. 94 ¢, Table 1). This represents an error of about 5%. Figures 1, 2 and 3 show that size is fairly closely correlated with age until the young are 320 days old, but thercafter it has little value for age determination. Closed Open Upper incisors wer jrcisors erupled erupted L 2. A NA $$$ Body lightly Head ard shoulders Body heavily furred Body fur absent furred heavily furred all over Testh absent; youag firmiy altoched to teal Eot gross Able to stand; unable Unoble fo stand erect ta hop Able to hon Head out of pouch on Compistely our of Conpleret, Camoletely jin pough wccasions pouch on o¢casigns out 2 3 4 5s 6 7ocm 1 4 es a —— 7 + eee | 1 2 3 4 5 6 7 a ? 10 NW 12 LF} 4 ifom nee 4 eal

[ tat! = 121 , = o 7 * ~ 10 d z | if Fig. 7. B £ foot lengtl b ig. 7. egression of foot length on cube s s) £ root of body weight of young Kan- ui de garoo Island wallabies reared in | sg captivity or in the field. F s o at f 2 ra ah ra 0 2 4 6 8 10 12 14 16 (WEIGHT)'3 an G. KR. MURPILY axn J. Rh. SMITH DISCUSSION The growth rate of young macropods in the field is extremely difficult to estimate. Shield and Woolley (1961) found that growth proportions of compound- and field-reared quokkas did not differ significantly, and so considered that the growth rates of field and captive animals were probably similar, A comparison of growth proportions between pouch young of curos from the field and from laboratory yards was carried out by Sadleir (1963), He found that there was generally little difference between the condition of young from the field and trom the yards and concluded that nutrition in the field was never poor enough to restrict the growth of the pouch young. Sharman et al. (1964) drew a similar conclusion for pouch young of the red kangaroo, They suggested that the comparatively stable environment of the pouch led to an “all or none” growth phenomenon and that the body measurements of the young provide a reasonably accurate indication of their age. The present study shows that the growth proportions of laboratory-and field-reared Kangaroo Island wallabies do not differ significantly in young aged less than 350 days. This is despite the observation that adult female wallabies in the field may be short of nitrogen and water at certain times of the year (Murphy, 1970), while laboratory-reared females were never short of food and water, It seems that the level of nutrition of female wallabics in the field is generally adequate so that growth of the pouch young is not restricted. It is possible that maternal malnutrition may severely affect the growth of the young, but il seems that this rarely occurs in the field. This study thus shows that size, as estimated from body measurements, provides a reliable indication of the age of laboratory- and field-reared Kangaroo Island wallabies until they are 320 days old. ACKNOWLEDGMENTS We wish to thank Dr, 5, Barker for his helpful criticism of this manuscript, and for his help on field trips. We also wish to thank the members of the Depart- ment who helped maintain the domestic colony and who also assisted on field trips. We are indebted to the Commonwealth Department of Education und Sciguee and to the Adelaide University Research Grants Committee for the provision of scholarships ta carry out this work. REFERENCES AnorewantrHa, H. G., and Barker, §., 1969. Introduction to a study of the ecology of the Kangaroo [sland wallahy, Profemnoden eugenii {Desmarest), within Flinders Chase, Kauguroo Island, South Australia. Trans. BR, Soc. 8. Aust 93; 127-133. Muneuy, C. R.. 1970. Haematological studies on the Kangaroo Island wallaby, Profenmodon. eugenii {Desmarost). Thesis (unpublished), Barr Smith Library, University of Adelaide. Sapurin, R, M. F. S., 1963. Age estimation by measurement of jocys of the curo Macropur tobystus Gould in Western Australia, Aust, J, Zool. 11: 241-49. Suaran, G. B.. Frerk, I. J,, aud Cavapy, |. H., 1964. Growth of the pouch young, tneth eruption and age determination in the red kangaroo. Megaleia rufe. C.8.1R.0. Wildl. Res. 9: 30-49, SHiewp, J. W., and Woorery, P., 1961, Age estimation by measuremunt af pouch young of the qnokka (Setonix brachyurus). Aust. J. Zool. 9: 14-33. A REVISION OF AUSTRALIAN GENERA OF ARCHAEOCYATHA BY F. DEBRENE* Summary The paper gives a brief reconsideration of the systematics of Archaeocyatha and tables of their classification. For the Class Irregularia, a first attempt is made to distinguish genera by standard diagnostic characters. An alphabetic catalogue gives revised diagnoses of genera occurring in Australia and their placing in families, together with other relevant information. Three new species which are type species of new genera are described in an appendix. A REVISION OF AUSTRALIAN GENERA OF ARCHAEOCYATHA by F. Desrenne* SUMMARY The paper gives a brief reconsideration of the systematics of Archaencyatha and tables of their classification. For the Class Irregularia, a frst attempt is made to distinguish genera by standard diagnostic characters. An alphabetic catalogue gives revised diagnoses of genera occurring in Australia and their placing in families. together with other relevant information. Three new spermes which are type species of new gencra are described in an appendix.. INTRODUCTION The aim of this paper is mainly to give the specialists on Archacocyatha the new definition of every genus established on Australian material, cither by the first anthors T. G. Taylor, R., W. R. and J. Bedford, or by subsequent desig- nation. In fact, original collections being acquired by different Museums, it is very difficult to have this work done; | am indebted to Professor M. F. Glaessner from the University of Adelaide, Dr. B. Daily, formerly at the South Australian Museum, Professor A. G. Fischer and Protessor B. F, Howell from Princeton Uni- versity, Dr. W. Ball from the British Museum (Natural History) who agreed to loan to me from the collections in their keeping, or for the last three, who gave me the opportunity of studying in their Department. Besides the types of genera and species, there are very numerous undescribed fossils; recently Dr, B. Daily and Dr. M. R, Walter kindly sent me further new material, A complete revision will take me at least one more year. The results of these studies will be published as a monograph by the “Muséum d'Tlistoire Naturelle”, Paris, not before 1972 or 1973. This is the reason why, on the advice of Professor Lehman, Director of the Institute of Paleontology of Natural History Museum (Paris) and Professor Glaessner, University of Adelaide, I decided to write a catalogue of the Australian genera. ; This paper gives for each genus; its type-species, and the place where it {s “epl, ws original diagnosis by the author of the genus, or when there is no diagnosis for the genus, as it often occurs in Bedford’s papers, the diagnosis of the type speciped with the omission of indications which are relevant only on the specific evel, —the present diagnosis after restudying typical material. —when necessary a discussion concerning the differences between original and present diagnosis or its affinities. —the place of the genus in present classification. Because of some considerations for the present edition, it was not possible to give an iconography of genera, Taylor's, Hill's and Debrenne’s photographs filling this gap for the present. Only new genera are figured here; 1 hope that complete illustrations will appear in my next monograph, Studics on outgrowths are not included: it would require a special work including Siberian and American specimens to state, as far as possible, their “Institut de Puléontologie, Mus¢um: National d'Histoire Natnrelle. 8, Rue de Buffon. Pasis-V", France, Trans, R. Soc, S. Aust, (1970), Vol, 94, 22 ¥. DEBRENNT, significance. Somphocyathus, Ardrossucyathus, “xocyathus and Metaldetimorpha are consequently not listed in this paper. Before the enumeration in alphabetie order of the Australian genera, T shall recall same principles of systematics and give fables in which each genus can be casily placed. CONSIDERATION OF THE SYSTEMATICS OF ARCHAEROCYATHA Till now, Archacocyatha are snbdivided into two main groups, Regulares ancl Irregulares (Class Hegularia Vologdin 1937 and class Trregularia Vologdin 1937) according to their first stages of devclopment, taking the apex of Dekisa- cyutlins as the type of the Regularcs. and the apex of Ahizacyathus, Alphactathus or Dictocyathus (avourding to different authors) as the type for the Inegulares. Regular Archacocyatha can be placed into a satisfactory classificalion estab- lisbed on simple rules (Zhurayleva 1960, Debrenne 1964). The changes in their classification come from new data. such as the discovery of new types of wall. or the recognition of homologies in outer wall development (Rozanov 1966-1969) They mainly concer supra-family levels, The classification of Irregulares is not su char, for several reasons. First of all, special studies on this group are not so numerous. Second, as they are of “irregular” appearance it is always difficult to establish the real spatial connections between the different elements of the inter- valluy) structures, This requires more than 2 or 3 oriented sections per sample. The result is that they are often described as “vesicular or taenioid intervallum slruetures”, “alveolar” or “scattered rods”. Tinportant genera as Archagocyathus Billings, Archueosycon Taylor (based on broken specimens which cannot be cut ta show how they are built up) or Dictyocyathus (the typc-specimen of which is lost and L was unable to find unquestionable topotypes in Sardinia, the Bornemann’s description and guration being too poor) are not well known, This lack in our knowledge stands in the way of establishing vules of classification for Irregulares, Thirdly, these forms are probably more primitive than Regulares; they do not build highly specialized skeletal layers as emmnplicated as the walls of Regulares, the main characteristic features of the adult are reached later during growth, and utten concealed by persistence of secondary exothecal or endothecal lamellae, bulges, buds or encrusting forms in which the intervallum frame is more or Jess disturhed. Development of vesicular tissue is not constant but frequent. Synapti- culae (or tangential links) occur in many cases; the more delicate the vertical frame and the more frequent the tangential links, the greater the irregular appear- ance of different sections. The individual development is of litte help for classification in such plastic forms, except for the distinction between Kegulares and Irvegulares, The indi- vidualization of the inner wall, the specialization of the outer wall and the radial aeangement of intervallum structures, the disappearance of secondary structures in the central cayity da not occur at the same level of growth amongst specimens from the same genus, or even from the same speties, Therefore, the primitive elements of apical parts (rods or booklets) represent potentially many kinds of adult structures in [rrestulares, and here they are most probably initially dependent on the environment more than in the strongly buill Regulares; thus they could not be used to define “recupitolated stages of evo- ition” and to state phylogenetic rules for systematics, as some previous authors haye suggested My studies on Australian Trregulares and on some Maroccan and Sardinian umes. generally of oldest stratigraphicul aye, leak me to believe that there is AUSTRALIAN CENERA OF ARCHAEOCYATHA £4 a strong tendency to build radial vertical structures which, finally produce adult forms very similar fo Regulares. 1 have proposed to call these structures “pseudosepta” and to distinguish several types (Debrenne 19894 p. 332). These pscudosepta are not always in true yertical planes like the septa of Negulares. As I have stated before, when the skeletal material is thin, the ennnec- lions are often distorted, On the other hand the pseudosepta are affected hy wavy disposition at the level of synupticulac, the opposing crests corresponding ta synapticulae. When the skeleton becomes more important, these features disappear and the genus looks regular, Tabulae are present, either as sieves linked to a peculiar horizontal development of synapticulae, or as independent structures, To distinguish in practice true Regular forms from Irregular ones with radial structures, When Uhe apex is unknown (the great majority of the specimens are lnvken above the apex), the strieture of the outer wall is the main feature, The porosity of pseudosepta is ulways important, even though this character is not yel well studied in Regulares. In Irregulares the pores have often various diameters; the pores occur ulong lines slanted obliquely upwards and outwards (vith a more or less acute angle) From the inner wall. and then gently curved near the outer wall. Tabulac und inner wall have peculiae arrangements, but they lave also some structures in common with Regnlares: synupticulae and vesicular tissue. generally more frequent in Irregulares, ure known in Regulares; so. their presence is wok snfficient to determine the class. The problem of Syringovcnema, which has radial honeycomb tubes is not clear. In some respects they resemble some “tube like-structures” built by the wavy sides of septa and flat synapticulae of Pycnoidocyathus type. Tn other ways. by the constant diameter of pores and the regular honeycomb construction, this genus resembles regular Archeocyatha, The holotype of the type species being poorly preserved, we need some more detailed studies. to settle this question. ‘This genus is temporarily placed as incertae sedis. The classification of Regulares is based on the following scheme: —prinitive structures of internal space extending {nto the apex give the definition of ORDERS. —laboration of the diferent types of interyallum structures give the definitiny af the SUBORDERS. —differcntiation of the outer wall (which is reached before that of the inner wall) gives the definition of SUPERFAMILIES. —at least differentiation of the inner wall gives the definition of the FAMILIES, —the GENERA are estublished on subcategories of the porosity of walls (section of canals, of annuli, disposition of and correlation between pores, increase of the porous surtace by vertical corrugations, etc.), and of porosity of interyallum structures. As a working hypothesis, I suggest for [rregularcs a table of classification based on the same pattern as ahove (Table A). As far as T know, this suggestion is not in opposition to their own growth pattern; but we must not forget that the differentiation of internal structive is established later than in Regulares and could be disturbed secondarily during growth by exothecal lamellae, budding bulges and so. on. The main argument in favour of this viewpoint is that attter wall (a superfamily character) is the most charactenstic feature separating Iyregulares with regular intervallum structures from Regulares. It is difficult to define the main types of intervallum and walls until the whole class is exhaus- lively restudied; I for myself huve not enough stratigraphical data (specially from upper part of the ower Cambrian) to establish the limits of subdivisions with 24 F. DEBRENNE certainty. Anyway, these new propositions are made to give rise to further dis- cussion. This is the first attempt to unify the criteria of classification as between Regulares and Irregulares, Future studies will improve this method, if acceptable, or End another satisfactory scheme for the whole phylum. TABLES OF CLASSIFICATION Class REGULARIA Order—MONOCYATHIDA—one wall. Suborder MonocyaTHina—internal space empty. Family—simply porous wall— Monocyathidae Menocyathus Family—simple tumuli— Tumuliolynthidae Tumuliolynthus (M. irregularis Benrorp) Order—AJACICYATHIDA—intervallum with radial partitions— Suborder Doxmocyatuma—intervallum with radial rods— Superfamily poxwocyTuacra—outer wall simple— Family—inner wall simple— Dokidocyathidae Dokidocyathus Acanthinocyathus Suborder PurapacyaTuinA—intervallum with only tabulae— Superfamily aprocyaTHAcea—outer wall simple— Family—inuer wall simple— Aptocyathidae Alphacyathus. Superfamily puraAPAcyaTHACEA—outer wall with alternating pillars— Family—inner wall with alternating pillars Putapacyathidae Putapacyathus Suborder AyactcyaTnina—intervallum with radial septa— Superfamily ayAcicyaTHACEA—outer wall simple— Family—inner wall simple, several pores per intersept— Ajacicyathidae Ajacicyathus Family—inner wall simple, one pore per intersept—Robustocyathidae Robustocyathus Stapicyathus Family—inner wall simple several pores + protection structures— Tennericyathidae Cadniacyathus Family—inner wall with ethmophylloid canals (sensu lato )— ?Ethmophyllidae Zonacyathus Family—inner wall with one carial + annular plates— Ethmocyathidae Ethmocyathus Tamily—inner wall with annular shelves— Cyclocyathellidae Thalamocyathus Family—inner wall with annular shelves and canals — Bronchocyathidae Cyathocricus Superfamily aNNULOCYATHACEA—outer wall with simple turuli— Family—inner wall with one pore Tumulocyathidae Dailycyathus (Paranacyathus margarita) AUSTRALIAN GENERA OF ARCHAEOCYATHA 25 Superfamily stemocyaTHAcEA—outer wall annulate— Family—inner wall annulate— Sigmocyathidae Sigmocyathus Suborder NocuonorcystHma—intervallum with radial septa and pec- tinate tabulae— Superfamily NocHoroIcyaTHAcrA (outer wall simple) — Family—inner wall with one canal + annular plates— Ethmopectinidac Ethmopectinus (lineatus pars) Family—inner wall with annular shelyes and canals— Glacssericyathidae Cricopectinus (dentatum pars) Glaessnericyathus (sizmoideus ) Suborder CoscinocyaTHtna—intervallum with radial septa and tabulae— Superfamily ERismacoscrvacrA—outer wall simple— Family—inncr wall simple— Erismacoscinidae Erismacoscinus (uustralis, bilateralis, textilis etc. ) Roxanovicoscinus (fonini)— asperatus pars) family—inner wall annulate— Stillicidocyathidae Stillicidocyathus Superfamily sicmocoscrnaceA—outer wall with protection structures— Family—inner wall annulate— Sigmocoscinidae Superfamily CaLyrrocoscinackA—outcr wall: frame + microporous sheath— Family—inner wall simple + spines— Polycoscinidac Polycoscinus Erugatocyathus Superfamily ALATAucyATHACEA—outer wall: tumuli— Family—inner wall simple + spines— Tumulocoscinidae Coscinoptycta Superfamily awsprycrocyaTnacka—outer wall frame | sieves— Family—inner wall simple— Anaptyctocyathidae Anaptyctocyathus Class IRREGULARIA Based only on Australian, West European, and North African material. Must be completed by studies of material from higher stratigraphic levels, Types of internal structures: —one wall; central cavity filled —two walls Types of intervallum structures: 1—Cylindrical rods radial and oblique: CHOUBERTICYATHIDA Il—Rods and booklets vertical and oblique: ARCITAEOPHARETRIDA [11—Pseudo-septa (plates with wide porcs to true radial plates with small, numerous pores the arca of which is less than that of the skeleton), without or with synapticulae, or with synapticulae and pscudo-tabulae (synapticulae in horizontal planes + sieves ) METALDETIDA IV—Stout radial septa without synapticulae and tabulae: PARANACYATHIDA V—Septa and independent tabulae: PARACOSCINIDA DUTER v WALL INNER WALL r acotaldina of muda) booklets ond janusntal pis 5 = - A oy a frome + sieves Fycrodacascinus: 4 Fume + miGtoporsus éheath Meicldetes oO a | i} Pulmert- 5 | siymod (ube per mersectur: Sigmotunga | eyathe,tus z po ee LE -- ---- 2 ----— Oh = ee B is = | Oflque tube per iierseptum 4 : A { | 3 one pore per “wierseptum” Archorufungia — a ------- Parocnzoqws ~~ eg _—$—$—______—. - inregular pare py staffolding of radial bonkiets and langental ros Copiercyothus a icame + sieves j ad - “a is 2 frame + mcropordus. sheath Métacoscinus = mac. Hike per mterseplum = Poe, phere estes a pi og gs a Pycnaida. | Flindersi — e ( obhque tube per inlerseptem Carns | cascines z - L ore pore pe "interseptum! irrequior pores senMolding of ‘odcl bookies end tarcenticl rods frome + sieves S frame + micropuraus sheolh 5 & a | sigmod lube per infefsepiun = 3 = | oblique: lube per inlersestum ctyceesein a ' Choubarti= one pore per “inrefseplim ‘yotnus: irreguiar pores 4-cneopharetra —————— cylindrical booklers connected itn Inrge opened Pseudo: sania rodia ond wavy pseudo —septa -odicl will pseudo - ‘golds rods ond bodkieis, vertica! ond abjique 3eudo sepla radia) wih pores Skeleton P septa. radial | (O%* °P* od) Asmuda-sepla oes = = radial plates| ‘ently radial alone with syrepe - [write syniopti= fwiln no orlew! with synapti-| with synupri-} wilful wii synoptiaeilh syqapte) clone wih onynipt [With synapt - with culoe culae ond = [synopticulae eulae gulag anv jsynapiliculas oulge Tea e and: | culo cujoe ind and singll versa labuloe tobuloe tabulue tabulae nite seavre and irregular | tabulde (Adapendent oblique pores robul - - Le ee be = L tha Classification—Table of Irregular Archacocy af Australia. io bea AUSTRALIAN GENERA OF ARCHAEOCYATHA Types of outer wall: —non-porous* —aperture of intervallom without independent sheath —irregular pores* —one pore linked to the septa —frame + microporous sheath* * present in Australia Types of inner wall; —irregular pores —one pore —one canal straight or sigmoid —trame + microporous sheath —frame + sieves —scaffolding of radial plates and flat tangential booklets. As this isa first attempt at a new way of classification I do not give names to supertamilies until subsequent studies corroborate or invalidate the underlying hypothesis (see Table A). Acanthinocyathus Breprorp and Brnrorp 1936 (pro Acanthocyathus Benrorp and Beprorp, 1934, p, 4, fig. 20) Type species. Acanthinocyathus apertus Beprorp and Brproxrp (1934, p. 4, fig. 20). Lectotype: British Museum (Natural History) S 4166. Lower Cambrian, Ajax Mine, Beltana, South Australia. Original diagnosis (R. and W. R. Bedford 1934, p. 4). The specimens agree with normal Archaeocyathinae in the possession of two walls: these are unite by avery scanty framework of delicate radial rods. The inner wall is a very open simple polygonal net. The outer wall is built up, as it werc, of a series of fused spicular elements enclosing large open spaces; spines or tubercules often project outwards beyond the general wall surface. The spitz, so far as known, has the same open net-like structure. Present diagnosis (After restudying typical material, Debrenne 1969a, p. 306), Two-walled cups with radial, horizontal or sometimes oblique cylindrical rods. The inner wall consists of a large porous net, with a mesh of irregular size formed by skeletal threads of constant thickness. The outer wall has large pores in quincunx; the skeletal tissue occupies a smaller area than the pores und carries long spines that are directed upwards and outwards, Discussion. R. and W. BK. Bedford thought that the inner wall was a scaf- folding of triradiate spicules. This sri gestion is not borne ont by observation: the outer wall is a porous sheet with the elongation of its horizontal skeletal parts into scales of an unusual size, Systematic position. Family Dokidocyathidae Beprorp and Breprorp 1936. Ajacicyathus Beprorp and Brpyory 1939 Type species by original designation: Archaeocyathus ajax TAyton (1920, p. 118, pl. la-e, j, k; pl. 3). Lectotype T. 1550a, University of Adelaide, chosen in an article in the press (Paleontologicheski Zhurn., Moscow). Lower Cambrian, Ajax Mine, Beltana, South Australia. Original diagnosis (R. and J. Bedford 1939, p. 73-74). “. .. Outer wall delicate with extremely fine pores distributed regularly... . Septa regularly arranged and 38 F. DEBRENNE uumerons, with pores rather remote and small, , . - Inner wall rather solid with revularly arranged pores, some being ‘stirrup-pores’, others not. . . ” Ywo-wallee cups, solitary or colonial with regular radial septa. Present diagnosis. Outer wall thin and regularly porous. Inner wall larger and stout, with regular pores; the inner wall and the septa are conmected by onc vertical row of stitrup-pores. Betwecu two adjacent septa, one or more rows of pores are observed, arranged together with stirrup-pores in a quincunxial pattern. Radial septa straight and stout, with few, or no pores. Discussion. The lack of porosity of septa is now considered as a yeveric charatteristic; the result of this being the individualisation of each interseptal loculus,. The presence of stirrup-pores at the inner wall is an important speci aliza- lion. When septa are completely non-porous, exchanges between adjacent loculi are possible only at the level of stirrup-pores. Systematic position. Family; Ajacicyathidac Beprory and Brprorp 193%. Alphacyathus Beproxn and Beprorn 1939 Type species by original designation: Dictyoryathus annularis BR. and W. li Benes (1936, p, 13, fig. 55). Holotype P 942, South Australian Museum, Adelaide. Original diagnosis (R. and W. RB, Bedford 1936, p. 13, fig. 55), “Small tubular form, .. . Outer wall pores are obscured in ihe type specimen, but a second specimen , . , shows small irregular pores... . TEe short comecting rods in the intervallum tend to anastomose into horizoutal rings... . The inner wall has small cireular pores...” Emended diaynosis (R. and J. Bedford 1939, p. 72, fig. 169). “ _, there is ‘a tendency of these (the rods) to be united by a single tangential row of synapticulae to form incomplete horizontal platforms a kind of forerumner of the tabulae of Coscinocyathus. This feature is specific and not cssentiul to the genus. ,..” Present diagnosis. Small cylindrical cups, with two simply porous walls, Tn the intervallum regularly spaced horizontal structures are present. They consist of eylindrical rods rising radially from the walls, but interrupted by tangential rods. There are no continuous bars from wall to wall, bit tabulac-like structures with more or less quincuxial pores. One inner wall pore at cach interradial space and at each horizontal level. Discussion, The horizontal platforms which were regarded by B. and J. Bedford as only specific structure are now considered as generic characters and detailed examination shows that there are no true radial rads connected by annular synapticulae, Systematic position. Family Aptocyathidae Konjushkoy 1964. Anaptyctocyathus Drmenne 1969 Type species Coscinocyathus cribripora KR, and W. R. Beprorp. Holotype: British Museum {Natural History) S. 4160. Original diagnosis (Debrenne 1969a, p, 340), Cylindrical cup, Intervallum with straight radial septa, in which the hexagonal pores occupy a much larger surface in proportion to the skelctal tissne, and irregular flat tabulae that are fincly perforated by very narrow pores, The inner wall is simple, with two rows of pores per interseptum, which are only weakly separated; in fact towards the upper part of the cup two neighbourimg pores may coalesce. The porcs of the auter wall are covered by knobs that are perforated by a central pore and a surrounding circle of six others, AUSTRALIAN GENERA OF ARCHAEOCYATHA ss Present diagnosis. The outer wall consists of a frame, with large pores, each of them being covered by a sieve, instead of low tumuli. Discussion, A. Yu. Rozanov recently pointed out three types of “double wall”. One of these corresponds to the structures of the outer wall of cribripora, Com- parison with material from the Soviet Union makes it certain that there are no true tumuli but double walls with a simple frame covered by non-independent sieves, Systematic position. Family Anaptyctocyathidae fam. nov. Archaeofungia Taycor 1910 Type species by monotypy: Archacofungia ajax Taytor (1910, p. 131, pl. 12, fig. 67, be. 25-). University of Adelaide No, T 1566, Lower Cambrian, Ajax Mine, Beltana, South Australia. Original diagnosis ( Taylor 1910, p, 131). “Cylindrical or conical forms without annulations, of small size with a comparatively narrow central cavity, They are characterised hy a very strong development of synapticulac and appear to form a transition genus between Archaeocyathus and Pyenoidecyathus, ., .” Present diagnosis. Small cylindrical or conical cwps with smooth undulations. ‘The apex is surrounded by exothecal lamellae and at the same level till a diameter of 10 mm. is reached, the central cavity is filled up by oblique porous tubes, which arise from the inner wall and become nearly vertical at the central part of the cup. The upper part of the central cavity is free of any skeletal elements; the inner wall has one horizontal canal per inierseptum. The outer wall, at first concealed by exothecal lamellae is of double porosity, the first frame with iegular pores is covered by a microporous sheath. Septa radial, with few pores, connected by imegularly spaced synapticulae (Debrennc 1989b). Discussion, The examination of typical material removes the doubts on this genus. It belongs to the Inmegulares. Regular forms with synapticulae have to be put in the genus Sibirecyathes votocmyx, which is not a junior synunym of Aréhaeofungia. Systematic position. Family Archaeofunyiidae fam. nov, Archaeopharetra Benronp and Brororp 1936 Type species by monotypy:Archaeopharetra typica BR. and W. KR. Benrorp 1536 p. 17, fig. '75, Holotype P,969, South Australian Museum. Lower Cambrian, Ajax Mine, Beltana, South Australia, —__ Original diagnosis (R. and W, R. Bedford 1936, p. 17). “Small irregular tubular organisms, the space within the outer wall filled with a mass of irregular trabecular and dissepimental tissue without central cavity or defined inner wall... .” Emended diagnosis (R. and J, Bedford 1937, p. 31), “... has centrally, in the upper part a kind of crude, irregular inner wail”, Present diagnosis, After restudying typical material: small cups with a non- porous outer wall horizontally striated by smatl annular corrugations. A true inner wall is defined for a diameter of 2 mm., but it could be concealed by the presence of skeletal bars and vesicular tissue in the central cavity; the interyalhim is filled up by irregular skeletal elements, bar- or plate-like, mainly placed in vertical or oblique position, but more or less radial, vesicular tissue is also present. The wpical part often consists of one wall and vesicular tissue only. Discussion. ‘The main new data is the presence of a truce inner wall com- menocing at a diameter of 2 mm.. and some tendency toa radial disposition of the elements. Systematic position, Family Archaeopharetridae fam. nov. wa F, DEBRENNE Bedfordcyathus Vouocum 1957 Type species by monotypy: Metacyathus irregularis Bevvorp and Benrore (1994, p. 6, fig. 29), Holotype: British Museum (Natural History) S489. Lower Cambrian, Ajax Mine, Beltana, South Australia. Original diagnosis (after R. and W, R. Bedtord 1934, p. 6). Large irregular cone, with wavy outer wall the inner wall followimg a similar contour: wide cavity... . ‘he outer wall has an underlying layer_of fairly large irregular pores masked by a finer network... , . Septa straight and delicate, casy to expose in transverse and tangential section, but not in radial section. No satis- factory trace of inner wall. Emended diagnosis (after Debrenne L969a, p. 360), The inner wall appears to be covered by an irregular microporous sheath which screens the simple pores. Discussion (after Debrenne F. 1969a, p. 355), There is no appreciable differ- ence from Metacyathus in the structure of the intervallum (apart from the abun- dance of vesicular tissuc) or in that of the walls. Consequently Bedfordcyathus is considered as identical with Metucyathus which is a junior synonym of Metaldetes, Beltanacyathus Brororp aid Bepyonp 1936 Type species by original designation: Beltunacyathus ionicus Bepronp and Beprorn (1936, p. 23, fig. 96). Holotype no. 86716, Princeton University. Lower Cambrian, Paint Mine, South Australia. Original diagnosis (R, and |. Bedford 1936, p. 23), “Large conical cups with remote coarse-pored septa; the outer wall an irregular fine mesh carried hy an underlying coarser mesh; the inner wall compased of exceedingly large regularly arranged canals leading upwards and inwards into the central cavity , . . coarse vertical Huting may be present.” Present diagnosis, Large conical cups, sometines with vertical fluting, Inter- vallum with two kinds of radial partitions: (1) complete septa, nmning from outer to inner wall, strong, pierced by regular pores—the area of whieh is smaller than that formed by skeleton—and (2) vertical radial plates, in the middle of each interseptum, arising from the outer wall, not larger than k of the space between the two walls, with no pores except one row against the outer wall, Outer wall double: the main frame consists of tubes of irregular polygonal openings, screened outwardly by a second microporous sheath. Inner wall with one pare tube per intersept, in horizontal and vertical lines. Tubes are long, set al a very acute angle with the wall. As far as known, radial septa are present down to the apex. Systematic pasition, Family Beltanacyathidae fam. nov, Cadniacyathus Benronp and Beprorp 1937 Type species by original designation: Cadniacyathus asperatus Benrows aNxp Bevrarp (1937, p. 36, fig. 152). Holotype 66616, Princeton University, lower Cambrian, Cadnia, Beltana, South Australia. Orivinal diagnosis (IR. and J. Bedford 1937, p. 86). “Archaeocyathina with vertical flutes to the outer surface, the furrows corresponding to the positions of the septa; the inner wall with scale-like hooks projecting upwards and inwards inte the central cavity, , ..” Present diagnosis. Conical cups with vertical fluting. The outer wall hus round pores regularly settled in quincunx. Sepla straight, pierced by small remote pores. The inner wall consists of 2 or 3 rows of pores per intersept lined up orizontally. A horizontal plate arises from the lower edge of each pore, and joins AUSTRALIAN GENERA OF ARCHAEOCYATIIA 51 laterally the veighbouring, one, so as to build a crude incomplete annular shelf which protected several pores, Jagged rim into the central cavity, Diseussion. his genus is very close to Tennericyathus nozaANnov 1969 which corresponds to the wucorrugated form of Cadniucyathus. Systematic position, Family Tennericyathidae Rozanoy 1969, Copleteyathus Beprorp and Beprorp 1937 Type species by original designation: Copleicyathus conferins Rinvore and Bepronp (1937, p. 29, fig. 116 A-19). Holotype 86741, Princeton University. Lower Cambrian, Paint Mine, Beltana, South Australia, Original diagnosis (R. and J. Bedford 1937, p. 29). ". .. A central cavity is present, at least in the upper part. Septa are numerous and are of ‘wire-netting’ character: although they are in places traceable right across the intervallum, they are very inregulur and more often curve and anastemose with neighbouring septa. The inner wall is of very unusual type, being a thick, felted mass of curved anastomosing tods continuous outwardly with septal mesh. . ...” Present diagnosis, Outer wall simple, rather thick, with pores less wide than skeleton. It is supported by some scarce spurs, coming out from septa, Septa ure straight, the pores of which are irregular in form and size, grading from round to nearly rectangular, Synapticulae present, rather numerous near the inner wall, The inner wall is of quite complex structure: It looks like a second intervallum, with three times more crowded radial plates, connected by tangential ones. This felted mass opens directly into the central cavity, without any other specialized sheath, Discussion. The septa are straight and radial and gencrally do not curve (as Bedford had stated). Their more or less irregular appearance depends on the orientation of sections, according us to whether they cross a skeletal part or pores, or cut tangential links. The intervallum and inner wall structures of the same pattern. Syslematic position, Family Copleicyathidae Bepronp and Beprorn 1937, Cascinaptycta Brom 1915 (pro Coscinoptycha Taycor 1910) ype species by subsequent designation of Simon 1939, p. 26: Coseinaptyeha cantolula Taycorn (1910, p, 14], pl, XI, fig, 60). Holotype by original designation, University of Adelaide 'T. 1594, Lower Cambrian, Ajax Mine, Beltana, South Australia, Original diagnosis (Taylor 1910, p. 141, pl. I, fig. 6, pl. VL, fig. 32, pl. XL, Ag. &)-63, fig, 68). “The shape is that of an extremely irregular and warped folded sheet, haying very little resemblance to a regular cup, but better described ay a warped bowl, of fabellate expansion. ... Tt is of a large size judging from fragment preserved. ... The intervallum is always quite small varying from one to two millimeters. The septa are regularly arranged, straight, ind numerous. Tabulac are present at rather remote but regular intervals, The genus is based on the general shape of the organism, The septate lamina has occasionally large re-entrant foldings, so that the outer wall becomes concave, . . - The cup like form probably grades into that of the present genus, ...” Present diagnosis. Bow]-shaped cups with few perforate to imperforate septa untl remote microporous tabulae. Vesicular tissue occurs when tersioid growths appear. Inner wall with 2 or 3 rows of pores protected by spines, Outer wall with ane row of siuple tumuli per intersept, perforated laterally. a2 fF. DEBRENNE Discussion, Material coming from the type locality enables us to state the position of inner (two rows of pores) und outer (one row of pores) walls, that corroborates Taylor's. view. Systematic position, Family Tumulocoscinidae zwurnavievA 1960. Cricopectinus gen. nov. Type species: C. dentulus sp. nov. pro Ethmophyllum dentatwn Tavior (pro parte) Taylor pl, XIV fig. 89, Holotype T 1589 RB, Diagnosis. Cup with radial septa, unpertorated except for one vertical row of pores near the outer wall, and pectinate tabulae, Outer wall simple, with pores contracted outwardly; inner wall complex: horizontal lined canals serve as aper- tures for several loculi. They extend inta central cavity by an annular shelf with deeply cogged free rims. Systematic position, Glaessnericyathidae fam, nov, Cyathocricus DreaeNNe 1969 Type species: Archacocyathus tracheodentatus KR. and W. KR, Bepronp 1934. Holotype: British Museum (Natural History) § 4754, Original diagnosis (DrsRenne 1969a, p. 318). Cup with a simply porons outer wall: straight, sparsely perforated radial septa and an annulate inner wall, Anouli consist of undulating, horizontal or slightly inclined plates, that are neither S- nor V-shaped; their axial rim is cogged. Systematic position, Family Bronchocyathidac R. and J. Beprorp 1936. Dailycyathus gen. nov. Type species by original designation: Paranacyathus margarita (Brovonp and Beprorp (pl. 1, figs. 4,5). Holotvpe 87214, Princeton University. Diagnosis, Large conical cups with regular radial septa and inner wall, but central cavity with skelctul structures arising from inner wall, near the apex, Adult stages could reach 4 large diameter with narrow intervallam, with vesicular tissue still present, Outer wall has one row of pores between 2 adjacent septa; each pore is covercd by an hemispherical cap perforated laterally; immer wall has. one row of stirrup-pores in front of each septa, Septa radial and imperforate except at the level of stirrup-pores, Discussion. The presenve of secondary skeletal structures in the central cavity is not a sufficient feature to place Dailycyathus amongst Irregulares; this kind uf filling is known in many specimens of true Regulares. On the: contrary, stirrp- pores and tumuli are typical features of Regulares. Systemutic position. Family Tumulocyathidae Knasnoprrya 1953. This genus is dedicated to Dr. B. Daily, formerly South Australian Museum, now University of Adelaide. Dictyvcoscinus Beprorp and Beprorp 1936 Type species by monotypy:Dictyocoscinus beltana Beprorp and Brprorgp, Holotype P 946, South Australian Museum. Lower Cambrian, Ajax Mine, Beltana, South Australia, Original diagnosis (R. and W, R. Bedford 1936, p. 14, fig, 62). Two walls connected by an open mesh similar to that of Dictyocyathus. At intervals a series of hovizontal sieve-plates fill the interstices of the mesh, forming a tabular structure resembling that of Coscinocyathus. AUSTRALIAN GENERA OF ARCHAEOCYATHA 33 Present diagnosis, Sma)l cups only known, Outer wall nou-porous. Innev wall with pore-tubes, alveoles, leading upwards and inwards into the central cuyity:; radial pscudo-septa, regularly made of plates, rather than rods, arranged in radial planes and pornscted by synapticulae. Some synapticulae are developed im horizontal planes. The holes defined by these synapticulac and the septa are sereened by sieves with rather regular pores, Systematic position, Family Dictyocoscinidae Benrorp and. Brprorp 1936. Dokidocyathus Taytor 1910 Type species by monotype: Dokidocyathus simplicissimus TAytor (1910, p. 146, pl. 13, pl. 77A, pl. 16, pl, 91-92). Holotype T 1589 AB, University of Adelaide, Original diagnosis (atter Taylor 1910, p. 146). “. . . Stout outer wall united to the yet stronger inner wall by remarkably few septa. The latter were particularly thick ,., , several Jongitudinal sections through the middle of the cups... (show); that intervallum was unoccupied by any connecting skcleton except a few strits which crossed it at remote intervals. . ...” Present diagnosis, Long cones, with outer and inner walls simply poraus, the intervallum between vertical rows of pores being strengthened by vertical ndges projecting into the intervallum from inner wall and outwards from outer wall. Radial partitions consist of flat plates settled in vertical plane, as septa with one large pore, the diameter of which is nearly equal to that of the intervallum. Discussion. The species included in Dokidocyathus with cylindrical radial rods rather than flattened plates generally occur at lower stratigraphical levels (Tommotian stage) than simplicissimus. After comparison with the Siberian raaterial and discussions with Russian specialists, I interpret the particular struc- ture of the type species as indicating a tendency towards construction of true septa from rods. Systematic position. Family Dokidocyathidae Benrorn and Brprorp 193A, Erugatocyathus Dyiwernne 1969 Type species: Coseinocyathus papillatus R. and W. BR. Beprorp (1934, p. 5, fiz. 12), Holotype: British Museum (Natural History) § 4153, Orivinal diagnosis (Debrernne 1969a, p. 334), Septa with remote round pares, Tabulae reticular... . The cireulay pores of the base of the coarsely porous outer wall are covered by a microporous sheath, in which each group of micropures consists of a central pore surrounded by 5 others. A skeletal tongne covers cach simple pore of the inner wall. Discussion. Till now, stellate or non-stellate inner walls are considered as sub-genus characters. Erugatocyathus is the unfolded form of Tomocyatfites ROzANOV 1960, but Rozanov (personal comnmunication) points ont that stellate or fluted interseptum spaces correspond fo in increase of porous surface and con- sequently could be of generic value. Systematic position, Family Polycoscinidae DEBRENNE 11)64. Ethmocoscinus Simon 1939 Type species by original designation; Coseinecyathis papillipora Brnvorn = > 5 ‘ 3 = = = & 2 ~ a o 5 NN ‘a om = 4 s 3 , 3 2a 2 = SS 8 ny ~ ey = Bo ee weds wsulberge Secreck 3 ren 7, , — ¥ = See Te. . od 5 — fced dune in cheer ind formet Incatiar o* vain iw cba er - B fedo pediment T Torrens puriece 5 silerete P silucete with pobplay Fig. 3, Diagrammatic section of the Beda pediment between Camp Hill and Beda Crevk. The Bookaloo dune field consists of fixed red dunes standing up to 6 m dhove the interdune corridors. They are about 70 m from crest to crest and trend roughly NNE and SSW in the southwest of the survey area, but.to the north ran ENE-WSW., Claypans occur in the interdune corridors and a few intermitlent, short streams flow to these centres of local dramage along the corridors and in some instances across the dunes, The dune sand is dominantly siliceous with a few grains of mica and feldspar; the quartz grains average 0-4 to 0-5 imum and are rounded to subrounded. Most of the grains have an iron oxide coating. ‘he dunes overlie the silerete surface in the Beda valley. This relationship can i: observed in many places, as for example a few metres west of the camp- site (Fig. 2). The Fereos plain is essentially that associated with the present Beda Creek and its tributaries. The plain is of limited extent, being restricted to the channel of Beda Creek, and the channels and very narrow valleys of its several tributaries. The channel of Beda Creek is braided and in many places bounded by blufls up to 7 mbigh. Some of these are of silcrete and it is clear that in the vicinity of Ellis Gully (Fig. 2), slight Inversion of relief has occurred (Fig, 3). The silerete of Elks Gully is alluvial, and this was clearly the old valley floor: the silcretc- capped plateaux, both to the worth and south of the present Ellis Gully, slope toward the depression. The present river however flows to the south of the auully. in the zone not so heavily indurated by silerete. Fields of fixed dunes up to 2 m high aceur in many places. This riverine plain merges with a narrow Jowlinel bordering Lake Torrens. Here occur coastal foredunes, principally of gypsurn (kupi dunes) as well as low, isolated mounds and salt fats. The salt surface is in places underlain by more than 80 m of Quaternary sediments (Johns, 1968). (c) Sequence of ecents: The Arcoona plateau, the Beda pediment and the Torrens plain are all surfaces of low relief which, sinve they cul across various members of the Precambrian sequence, are of erosional origin. The three surfaces occur at quite distinet elevations and aré separated by more-or-less steep escarp- ments, so that the landform assemblage presents a stepped appearance, None of them displays evidence of having been inundated by the sea, by lake waters ov by thick sequences of alluvium. Thus the higher Arcoona surface is evidently of preater antiquity than the Beda surface, which is in turn older than the Torrens surface, The latter is of recent age but lack of fossiliferous superficial deposits, genetically associated with the two older plain remnants, precludes the possibility CEOMORPHOLOGY OF ARCOONA PLATEAU AND TENT HILI, KECION 4 of dating them directly. The longitudinal duncs of the Bookalao field in the Beda Creek urea occur mainly on the Beda pediment, thuugh Usey spill over on to the Torrens plain near Beda Hill. Thus all that ca be said concerning their age fs that they postdute the period of silcrete development. In summury the following sequence of events can be reconstrueted;— 1. Erosion of Arcoona surface. 2. Major lowering of baselevel; stream rejnvenalion, erosion of Beda pediment; developrent of silcrete; weathering of scarp foot zaue. 3. Accumulation of Bookaloo dune field, 4, Slight negative baselevel movement, dissection of Beda surface, and development of narrow Torrens plain; local accumulation af dunes, lake and riverine deposits. aT z iil Tent Hill surface Yorkey surface . fig. 5 Corroberra surface Spencer surface & Gul! Orwlet 5 E tte Woolshed surface E =] legeon, mud teat hin. 8 Fig. 4. Morphological map of the Tent Hill region (ovation of Big. 5 shown}. 6b G. BR TWIDAT.E, J. A. SIEEPILERD ano BR. M. THOMSON The Tent Hill Region (a) General setting: The Tent TLill region mapped during this investigation comprises the assemblage of plains and plateaux north and west of Port August (Fig. 4), Field mapping did not extend south of the Eyre Highway. The Lind- orm assemblage has evolved ona sequence of flatlying Precambrian sediments which overlap onto the Gawler platform, and which are the approximate equiva- lents of the sediments of the Beda Creek area and of the Matrinoan beds exten- sively exposed in the ncarby Flinders Ranges, The sequence includes two prominont resistant saudstones, the Simmens Quartzite and the Corraberra Sandstone, which are interbedded with siltstones and shules, The landform assemblage of the Tent Hill area reflects the disposition af the sediments and their differential weathering and erosion by streams, which have graded to variotis busvlevels through geological time, (b) Morphology: The Tent Hill region consists of a series of stepped erosion surfuees which cut at low angles across the near-herizantally disposed strata, ancl which are separated in most places by precipitous svarps. The lower surfaces however in some areds merge imperceptibly one with another. The surfaccs are shown in Fig. 4 and are described in sequence from highest to lowest. The Tent Hill plateau surface is preserved in prominent plateaux, mesas and buttes (Pl. 2, Figs. Land 2) which are sufficiently numerous and widespread to sug- vest that they aro part of a formerly contiguous surface. The plateaux stand some 250-240 m above the principal plains and attain heights 300-330 m above sea level. Mast are capped and pretected by Simmens Quartzite and arc bounded by steep faceted scarps, many of which display stractural benches. In detail no one stratum eaps the pluteau; the surface cuts across mauy individual beds and is therefore of erosional Lype, The steep bounding scarps surrounding the Tent Hill surface lead down to quite steep debris slopes (inclination 10° to 15°) which merge imperceptibly with pediments inclined at 3° to 4° to the horizontal, though becoming gentler toward the axes of the valleys, These smooth, gently sloping pediments, which cut icras$ various members of the argillaceons sequences, form the Corraberre strfuce. The Corraberra pediment is notable for the silerete developed disvot- tinuously upon it. Silerete has been mapped in adjacetit areas to the west (Dalgarno, Johnson, Forbes and Thomson, 1968) and west und north of [esse (Fig. 1), but many of these occurrences in the Tent Hill region have not pre- viously been recorded. The most massive silerete oceurs on the toes of the Corraberra pediment. Here the silcrete contains small rounded quartzite pebhles, and is probably a silicified alluvium. Silcrete is also quite well developed in searp foot situations as, for example, neay Corraberra HUS, and on the southern side ot South Tent Hill. In the latter region it ulso occurs as long ribbons extending down- slope from the scarp foot zone along stream beds. In several areas. the Corrahera pediment is separated from the backing escarpment by scarp foot valleys (Figs. dand 5, Pl. 2, Pig. 2). On the lony pediment slopes between the scarp foot and the old valley axes. silerete is absent, These long, gentle slopes are characterised by the development of gilgai and Isy the surface accumulation of gibher, most of which consists of sandstone fragments, Where silevete of sandstone underlies the Corraberra pediment, the slopes hounding the low plateau are steep, though only 4 to 3m high, But where the witsber farms the surface the bordering slopes are more gentle and the next lower plain, the Woolshed pediplain, merges wilhiout pronuunced break of slope with the Corraberra surface. GEOMORPHOLOGY OF ARCOONA PLATEAU AND TENT ITILL REGION 61 Tent Hill surface, scarp 2] Corraberra surface N | Omile } [Al es | Woolshed ond Yorkey surfaces Gkm, 15 Vig. 5. Morphological map of ‘lent Hill Suuth and the adjacent areas showing the scarp foot epression deycloped on its northern and western sides. The Woolshed pediplain is the most extensive morphological unit in the Tent Hill region. It has a low inclination (1° to 2°) but nevertheless cuts across various lithologics. It is smooth and little dissected except near its eastern or Spencer Gulf margin, and is capped by a veneer of clay and gibber, prominent constituents of which are quartzite and silerete, The Woolshed plain can on this account be considered a pediplain, though a sharp break of slope at the upper margin is not everywhere present, As is the case with the Corraberra pediment, there are, within this erosional surface, areas of local deposition: some are riverine, some aeolian, the latter taking the form of fixed sand dunes. Gilgai are also widely developed on the surface and the streams draining this surface have cut deeply into the scarp foot zone of weathered rock. Near Corraberra H.S. laminated sediments and gypsum accumulations suggest that there was formerly impedance of local drainage in such a scarpfoot valley, giving rise to a shallow lake. é2 G. BR. TWIDALE, J, A, SHEPHERD axp R. M. THOMSON The Woolshed pediplain is dissected by streams, Most of the resultant valleys are shallow, but in the east they are deep and V-shaped in cross section, They open Gut to a narrow plain bordering the estuarine northerly extension of Spencer Gulf, This plain is called the Yorkey surface. It stands 3 to 30 m lower than the Woolshed surface, Claypans, including a large one northwest of Port Augusta (Fig. 4), are well developed on it, and there are also fixed dunes. But the Yorkey surface has also suffered dissection and a narrow Hat horders the estuary—the Spencer surface. It is some 6 ta 7 m lower than the narrow Yorkey plain and displays mainly depositional Forms. though there are some narrow erosional plains, Many of the estuarine and riverine deposits have been blown into dunes, and various areas of the estuarine flats have been isolated ta form quite large lagoons. (ce) Sequence of events: The several planate surfaces described all cut across various and varied members of the Precambrian sedimentary sequence and ate therefore essentially erosional in character. There has been considerable deposition on the Spencer surfuce, but apart from this, there is no evidence of incursions of the sea since the development of the surfaces, They can, therefore, he regarded as stepped series in which the higher surfaces are of greater antiquity than the lower, The dunes which occur on the Woolshed, Yorkey and Spencer surfaces are nat necessarily of similar age; ull that can be said at present is that they formed subse- quent to the erosion of the surfaces on which they stand, Thus the following sequence of events can be proposed: — 1. Erosion of Tent Hill plateau. 2, Deep erosion of streams and valleys, erosion of Corraberra pediment, patchy development of silcrete, and marked weathering of scarp foot ZOLLe. 3, Slight stream rejuvenation, denudation of Corraberra pediment over wide area, and extensive development of Woolshed pediplain; erosion of scarp foot valleys. 4, Moderate stream incision, and development of narrow plain along Gulf shore—the Yorkey surface. 5. Stream rejuvenation to level probably lower than that of present ocean surface. 6. lise of svalevel, development of narrow plain in association with this Jevel, and infilling of the arm of the sea—the Spencer surface. It is to be emphasised that each of these stream sejuvenations continued its inland extension even after the next phase of incision had been initiated. Thus the surfaces continue to extend, the lower surfaces growing and migrating inland at the expense of the next higher. Hence, though the scarp foot valleys were pre- pared by localised weathering during the Corraberra period, and were first eroded during the Woolshed development, they continue to be extended; in this way, the area of both the Tent Hill and Corraberra surfaces continues to be reduced. Denudation Chronology (a) General remarks: A comparison of the surfaces of the Beda Valley and of the ‘Tent Hill review strongly suggests that, though the latter region displays surfaces of limited extent close to the present sealevel and additional to those whieh occur in the former, the two areas have much in common, In particular the Arcoona and Tent Hill surfaces, and the Beda and Corraberra surfaces, appear equivalent. The Beda and Corraberra surfaces both bear silerete, which can be traced, albeit discontinuonsly, between the two study areas. Thus some 3 km east UEOMORPROLIGY OF ARCOONA FLATEAU AND TENT HILL REGION 43 of Bookaloo R.S., within the Bookaloo dune field, silerete is exposed in the Beda Creek track. Again, about 1 ktm south of Hesso H.S. sandstone exposed in a low plateau standing some 7 to 8m above the plain level displays heavy surficial silicification and silcrete coatings. It thus seems probable that the silercte of the Beda and Corraberra surfaces is part of the same development, and can therefore be used as @ stratigraphic marker. (bh) Age of silerete: It is just as inyportant that the silerete allows the only possibility of dating the surface un which il oveurs. thus providing a time marker in the relative sequence of events. Extensive sheets of silerete ocvur in the northeast of South Australia and the adjacent areas of Queensland. There it is developed on strata which include the Winton Formation of upper Cretaceous and lower Tertiary age. Thus, the silerete postdates the earliest Tertiary. On the other hand, the folded and dissected silercte surface is in several places overlain by equivalents of the Etadunna Formation; the age of this Formation is problematic, though, in all likelihood, it is Pliocene, Thus the silerete so widespread in central Australia developed in the middle Tertiary (Wopimer, 1963; Wopimer and Twidale, 1967). This stratigraphically determined date was upparently confirmed by radio- metric datings of a dolerite dvke alleged to intrude silerete near Roma in south- eastern Queensland (Langford-Smith. Dury and McDougall, 1966); subsequent investigations, however, suggest that the stratigraphic relations of the two are questionable and that the significance of the 22-7 million years determined as the age af the dvke is unclear so far as the silercte is concerned (Exon, Milligan and Day. 1967). A imiddle Tertiary silcrete has also been reported from the northern Willochra basin, in the southern Flinders Ranges (Twidale. 1966), the cvidence again being stratigraphic. Another silcrete of limited areal extent and of Pleistocene age has been reported from the urea west of Lake Eyre (Wopmer and Twidale, 1967), It differs from the main, massive silerete of central Australia in that the: latter consists of quartz fragments and crystals set in a matrix of finely divided quartz while the matrix of the younger rock is opaline. It is reasonable and conccivable that all sileretes were orivinully opaline but that, with the passing of time, crystalline structure developed. Both thin-section cxamination and X-ray diffraction show all the silcretes of the Beda and Curraberra surfaces to be wholly quartzitic. Thus all date from the middle Tertiary—probably Miocvene—and indicate that the surfaces on which they are preserved are also approximately of this age. (c) Ages of erosion surfaces and Rorrelisiyata As the Bookalon dunes rest upon the silcrete without themselves showing signs of secondary silicification, they, like the Torrens plain in the Beda Creek area, and the Woolshed, Yorkey and Spencer surfaces in the Tent Hills region, must postdate the middle Tertiary. The Arcoona and Tent Hill surfaces, on the other hand, being higher, must be older than the middle Tertiary. The crucial evidence is reported by Johns (1968 pp. 7-13). The basal lacustrine sediments beneath the present bed of Lake Torrens, resting un folded Cambrian Strata, are, on the evidence of their con- tained plant fragments, of Kocene age. Though the Torrens lineament is an anvient structure, stratigraphic evidence from bencath the present bed of Lake Torrens suggests that a phase of dislocation began in the Eocene, and continued throngh to the (?) Miocene. It seems likely that the major stream) rejuvenation and dissection of the Arcoona plateau was initiated by faulting in the Eocene. Dissection of the broad valleys and the development of the Beda surface during the early Tertiary (Eocene-PMincene) contributed sediment to the lake then 64 C.R, 'FWIDALE, J, A. STITPHFR AD any KR. M. THOMSON occupying all, or part, of the Torrens sunkland. The Arcoona surface is thus essentially of late Mesozoic age. Mesozoic surfaces border the Great Artesian Basin on its western side in the Peake and Denison Runges, in the Granite Downs area (Wopfner and Twidale, 1967), in the ranges of central Australia (Mabbutt, ery and in northwest Queensland (Twidale, 1956). The Arcoona plateau-Tent Hill surface is probably part of this ancient land surface. The plateau surface, no doubt of similar age, extends. south of the Tent Hill region te Whyalla and beyond, and can alsa be extrapolated into the Gawler Ranges, where it forms a summit surface. This con- clusion is confirmed by the observed westward extension of equivalents of the Beda and Corraberta surfaces into the valleys and plains of the Gawler Runges. Differential subsurface weathering and preparation of inselbergs on Eyre Penin- sula occurred beneath this Mesozoic surface, which is much earlier than has previously been supposed (see Twidale, 1962), It is suggested above that the disruption of the Arcoona plateau and the initiation of the Torrens sunkland were simullaneous events caused by down- faulting on the eastern side of the Torrens Jincament. The erosion of the Beda surface with its associated silcrete and of its southerly equivalent, the Corraberta surface, had occurred by the end of the Miocene, presuming this to be the age of the silorety, This coincides with the presumed end of Tertiary lacustrine sedimentation in Lake Torrens, Rejuvenation followed, Earth movements may again be respon- sihle, as Pliocene or pre-Pliocenc faulting along the Lincoln lincament, a complex fault zone linked to the Torrens lineament, bas been suggested by Miles (1952), Ta the Lake Torrens arca this caused renewed infilling of the depression, a process which has continued to the present time, This later phase of tectonism may have initiated the development of the Woolshed pediplain in the Port Augusta region, In appearance and location with respect to the mid Tertiary silerete surface, the Woolshed surtace is very similar to the gypsite surface extensively developed in the Lake Eyre basin (Wopfner and Twidale. 1967) und the two surfaces may be equivalent. Vowever. in this southern area, because of its proximity to the sea, surfaces were developed additional ta those represented in the Beda valley. They were associated with Pleistocene glacio-custatic movements of sealevel, but it is not possible to be more precise. Reliance on vertical differences hetween surfaces is rendered dubious hy the possibility of recurrent fault dislocation along the Torrens and Lincoln lineaments. Thus the Yorkey surface cannot be precisely dated simply by matech- ing its present elevation with an appropriute alleged high Pleistocene sealevel. The Spencer surface is largely depositional and the zmount of infilling, and hence the degree of sealevel lowering implied, is not known. All that can be said of the Yorkey and Spencer surfaces is that they are of Quaternary age. Slope processes and behaviour The preservation of these erosional surfaces, lwo of which ure of vreat antiquity, is due to their hard cappings which induce a particular slope mar- phology and behaviour, Fach of the planate erosion surfaces of the Beda valloy and Tent Hills regions bears a capping, the nature and effectiveness of which varics from surface to siirface and from place to place upon the surfaces, but which in all cases cxerts a protective function. These resistant cappings arc of three types: —- 1. Quartzites such us the Arcoona Quartzite in the Beda valley and environs and ihe Simmens Quartzite in the Port Augusta region. 2. Silercte. GEOMGHPHOLOGY OF ARCOONA PLATEAU AND TENT HILL REGION 65 3. Accumulations of more-or-less coarse stone, the well-known gibber. In the Beda region, the gibber consists predominantly of platy sandstones with desert varnish as well as quartvite fragments. These stones are concen- trated as surface layers and originate in several ways: (a) They may form as a result of mass movements on slopes (creep, slides, flows, avalanches}, which cause coarse debris to migrate from exposures on the scarp slope and spread on to the upper pediment slopes. (b) They may be derived from the weathering of bedrock; the coarser Fraction may be relatively concentrated, due ta the removal of fines from the surface by wind and running water. (c) The wetting and drying of clays results in expansion and contraction and the development of gilgai (see e.g. Hallsworth, Gibbons and Robertson, 1955). During wetting and. expansion both fines anal coarse debris are thrust upwards, but when, after desiceation, crack- ing takes place, only the fines can return to depth doww the com- paratively narrow fissures, so that the fragments remain at the surface (Springer, 1958). These eappings in varying degree protect the land surfaces on which they occur. The quartzites and sileretes are more effective in this respect than is the gibber, but even the latter is more resistant than the shales and siltstones beneath it. The cappings also influence slope morphology and behaviour, The presence of a fesistant capping of quartzite or silerete ensures the development of a bluff and hence of a faceted slope. The quartzites ure commonly underlain by siltstones or shales, the silerete by weathered sediments which are part of the silcrete weather- ing profile, Thus weathering and erosion of the upper part of the slope, where the resistant strata outcrops, and the lower, underlain by weaker beds, are greatly in contrast, The lower slope, besides being built of inherently weaker beds, suffers marked weathering and erosion of the scarp foot (Twidale, 1962, 1967) which is consistently worn back and regraded, causing the subsequent undermining of the hard stratum at the bluff This is manifested in the development of caverns, ia the gradual unbuttressing of joint blocks in the bluff, in the downslope flowage of materials like gibber and, in general, on the collupse and recession of the bluff. The undermining and collapse of the bluff leads to a particular mode of development of the debris slope. Below the points at which a bluff has collapsed, detritus from the bluif spreads out over the debris slope. The fragments derived from the blolf are coarse, and protect the soft rocks of the debris slope, while erosion, principally in the form of regressively eroding gullies, occurs on the unprotected sectors between these vencers of gibber. But this leads to the bluffs being undermined in new areas, to their collapse, and to the hitherto unprotected areas of slope being protected. Meanwhile, the earlier veneers have suffered weathering; and the washing out of fines causes the eventual downslope moye- ment of the coarse frayvments, so Unit these protected zones are avain vulnerable to gullying and recession. In this way the focus of attack switches from place te place on the debris slope, and hence on the bluff, The process, which was described 30 years ago by Kirk Bryan (1940) was called by him gully gravure, Its cflect is particularly well displayed beneath the silerete capping in Ellis Gully, and heneath the gibber veneer in Swallow Cliffs, both in the Beda Valley (Pl. 2, Fig. 3). Thus, because of the particular slope budget (Tricart, 1957; Twidale, 1960) which prevails in these localities, faccted slopes tend to be developed and main- tained, as Jong as the resistant capping persists. Slope retreat or recession which 66 CG. BR. TWIDALE, J, A, SHEPHERD ann R. M. THOMSON is dominant in such lithological, structural and climatic environments continues until such time as the hard capping has been eliminated. Once this has been achieved, the bluff disappears, as has occurred in the Sugar Loaf, in the Tent Till region, and slope decline becomes prevalent, as in the Arcoona hills region, unless or until the concentration of lag or gibbcr becomes sufficiently marked to produce a new protective veneer, But because of the prevalence of scarp retreat, ancient erosion surfaces are preserved and are prominent features of the present land surface. REFERENCES Bryan, K., 1940. Gully gravire—a method of slope retreat. Jour, Geomorph. 8; 89-109. Dareanno, C. R., Jonnson, J, E., Forses, B. G,, and Tuomson, B. P., 1968. 4 mile map sheet Port Angusta. Ceol. Surv. S. Ausir, Exon, N. F., Mrutican, E, N., and Day, BR. W., 1967. Ave of the duricrust in southern Queensland. Austr, Jour. Sei., 30; 110. Hariswoum, E. G,, Rosertson, G. K,, and Gnsnons, F, B., 1955, Sludies in pedogensis in N.S.W. VII. The gilgai soils. Jour. Soil Sci, 6; 1-31. Jonns, BR, K., 1968, Investigation of Lakes Torrens and Gairdner. Geol. Surv. §. Ausir, Rept, Incest, 31, 90 p. Lancronp-Ssarer, T., Dory, G. H., and McDouca., 1. 1966. Dating the duricrust in sowth- ern Queensland. Austr. Jour, Sci. 29; 79-80. iba tr J. Be 1965, The weathered land surface in central Australia, Zeitschr. —. Geomorph. 9; 82-114, Mires, K, R., 1952. Tertiary faulting in northeastern Eyre Peninsula, South Australia, Trans. Roy. Soc. S. Austr. 75; 89-96. Spricc, R, C,, 1952. Sedimentation in the Adclaide Geosyncline and the formation of the continental terrace, pp, 153-159 in Sir Douglas Mawson Anniv. Vol. (Ed. M. F. Glaessner and E, A. Rudd), Univ. Adel, 224 p. Sraincrn, M. F., 1958. Desert pavement and yesicular layer of some soils of the desert of the Lahontan Basin. Proc, Soil Sci. Soc. Amer. 22; 63-66, Tricant, J., 1957. L’évalution des versants. L’inform, géographiuue. 108-115. Twinate, C, R., 1956, Chronology of deundation in northwest Queensland. Geol. Soe. Amer, Bull., 67: 867-882. Twmatr, C. R., 1960, Some problems of slope development, J. Geol, Soc, Aust. 6; 131-148, Twipate, C. R,, 1962, Steepened margins of inselbergs from northwestern Eyre Peninsula, South Australia. Zeitschr, #. Geomorph. (N.S.) 6: 51-69. : Twipare, C. Ri, 1966. Chronology of denudation in the southern Flinders Ranges, South Australia. Trans. Hoy. Soc. 8. Aust. 90: 3-28. TwopaLce, C, R., 1967. Origin of the piedmont angle. As evidenced in South Australia. J. Geol. 15: 393-411. Twmare, C. R,, and Foars, M. H., 1969. Landforms Uhistrated, Nelson, 154 p. Worrnen, H., 1960. On some structural development in the central part of the Great Artesian Basin. Trans. Roy, Soc. S. Aust. 83: 179-193, Worrnek, H., 1963. Post-Winton sediments of probable upper Cretaceous age in central Great Artesian Basin. Trans, Roy. Soc. S, Aust. 86: 247-253. Worrnen, IT, and Twinaue, C. R.. 1967. Geomorphological history of the Lake Eyre Basin, Ch. 7, pp, 118-143 in Landform Studies from Australia and New Guinea. (Rd. Jennings, J. N,, and Mabbutt, J. A.). A\N.U. Press, Canberra, 434 p. Fig. Fig. Fig. Fig. to tw GEOMORPHOLOGY OF ARCOONA PLATEAU AND TENT HILL REGION 67 Pate 1 . Panorama west from camp site (see Fig. 2). Note the domed plateau of Camp Hill (part of the Arcoona plateau—A); intense weathering, particularly the development of silcrete, beneath the toe of the pediment which represents the Beda surface (B) and of which Ellis Hill is part; and the lowermost or Torrens surface (TT) which takes in the present channel of Beda Creek. (Photo. C. R. Twidale. ) . Scarp foot valley on the east side of Camp Hill, with Jans Nob and Jennies Flattop on the right horizon, The patches of white beneath the three residual hills indicates intense weathering. (Photo C. R. Twidale. ) Silcrete profile exposed in Ellis Gully: columnar silcrete (C) is underlain by kaolinised rock (K) which, atypically, contains calcrete nodules. This is in turn underlain by bedrock (B). (Photo. C. R. Twidale. ) PLATE 2 . Surfaces of low relief near Corraberra H.S. Note the scarp foot depression at the head of the Corraberra surface. (Photo. Robyn M. Thomson. ) . Panorama of Tent Hill South, seen from the southwest (see Fig. 5). Note the plateau level of the Tent Hill surface (A), the pediment remnants of the Corraberra surface (B) and the moat or cutters formed by the strong scarp foot erosion of intensely weathered bedrock, These scarp foot valleys represent the Woolshed surface. (Photo, C. R. Twidale. ) . Swallow Cliffs, near the mouth of Beda Creek, showing a stage in the operation of gully gravure. The superficial layer of river gravels (G) has in several places been undermined through the development of gullies in the soft shales exposed in the cliffs below. Hence gravel has poured down and partially filled these gullies (a), which are thus protected against erosion, The exposed shales (b) on the minor divides between gullies are more vulnerable and in future these will be eroded, gullies will form, the gravel will be undermined and will pour into the newly created depressions located between the present small valleys. (Photo, C. R. Twidale,) THOMSON R. Twmare, J. A. SHepHern AND R, M. ” , Cc, PLATE 1 2 do33e|4 soiuuar GON suer II!H dues des sans JUaWIPadg epag IH sila AI|NE) si[y a) PLA’ IN |. A. Saepuerp AND R. M. THomsc . R. Twwate. | C Aay104 ITH tel p1daqnise7 PEYys}OoAA PHYSICAL AND CHEMICAL LIMNOLOGY OF THE BLUE LAKE OF MOUNT GAMBIER, SOUTH AUSTRALIA*+ BY A. TAMULY* Summary The Blue Lake at Mount Gambier occupies an area of 0-603 Km? (= 149 acres) at water level, and holds on the average, a volume of 36-8 million m (= 8090 million gallons) of freshwater. The mean and maximum depths of 61 and 77 metres are typical of the regular bowl-shaped basin, which resulted from the collapse of a volcanic crater about four thousand years ago. Indications of groundwater recharge and a daily passage of about 0-45 million m* (= 100 million gallons) of freshwater through the lake are still tentative. The change in water colour in November coincides with a Secchi Disk transparency of about 58% of that in September, and with an appreciable oxygen-deficit throughout the water column. Although the lake waters contain an equilibrium concentration of calcium, the ionic product never exceeds the solubility product of calcite at the observed pH and water temperature. This chemical state in water precludes precipitation of calcium carbonate, and as such, the change in water colour cannot be consequent to carbonate precipitation in the summer season. It is suspected that the blue colour is caused by fluorescence of dissolved organic matter, probably of allochthonous origin, which builds up seasonally in the upper layers of the lake waters. PHYSICAL AND CHEMICAL LIMNOLOGY OF THE BLUE LAKE OF MOUNT GAMBIER, SOUTH AUSTRALIAt by A. Tamury? SUMMARY The Blue Lake at Mount Gambier oeeupics an area of 0:603 Km? (= 149 acres) at water level, and holds on the average, a vohime of 36°8 million im? (— 8090 million gallons) of freshwater. The mean and maximum depths of 61 und 77 metres are typical of the regular bowl-shaped basin which resulted from the collapse of a volvaniv crater about four thousand years ago. Indications of groundwater recharge and a daily passage of about 0°45 million m3 (= 100 million gallons) of freshwater through the lake are still tentative. The change in water volour in November coincides with a Secchi Disk transparency of about 58% of that in September, and with an appreciable oxygen-deficit throughout the water column. Although the luke waters contain au equilibrium concentration of ealcizm, the ionic product never exceeds the solubility product of calcite at the observed pH and water temperature. This chemical state in water precludes precipitation of calcium carbonate, and as such, the change in water colour cannot be censequent to carbonate precipitation in the summier season. It is suspected that the blue colour is canine by_ fluores- cence of dissolved organic matter, probably of alluchthonous erigin, which builds up seasonally in the upper layers of the lake waters. INTRODUCTION The Blue Lake in the Mount Gambier district of South Australia (37°50’S, 140°46’E) is known for its seasonal change of colour: grey during winter, a luminous blue during summer, The transition from grey to blue about November each year occurs quite suddenly, compared to the gradual reversal to grey from mid-summer unti] April. Several theories. including inorganic precipitation of calcium carbonate and a redox reaction of a plant dye, have been suggested to account for the blue colour, but lack of experimental evidence throws some doubt upon the validity of any of these theories, The present paper reports the pre- liminary results of un investigation prompted by the lack of such evidence, The hydrogeology of the region around Mount Gambier was described by Fenner (1921) und Ward (1941). Limited chemical information on the Blue Lake was also published by Bayly and Williams (1964). The limnology of this minute caldera is virtually unknown. In order to study some of the important aspects, the author visited the Blue Lake in September and November of 1967, and again in January and July of 1968. PHYSICAL LIMNOLOGY a. Earlier Studies Fenner (1921) and Ward (1941) pointed out that the Blue Lake was recharged via a direct contact with groundwater in the Tertiary and Pleistocene rocks and that there was a high degree of correlation between the cumulative rainfall and the lake level. Beaney (1957) brought the results up to date with a correlation coefficient of 0-85. The results of Bayly and Williams (1964) are informative, yct insufficient, to describe the seasonal regime in the lake. These “The Horace Lamb Centre for Oceanographical Research, The Flinders University of South Australia, Bedford Park, South Australia. + Research Paper No. 28 of the Horace Lamb Centre, Trans. K. Soc. S. Aust. (1970), Vol. 94. 72 A. TAMULY authors expressed similar views with regard to direct contact with the ground- water, and reported that the annual marine atmospheric cycle largely determined the relative ionic proportions of salts in the lake. As a result, the lake waters on analysis rendered a relatively different composition to the surrounding ground- water, Periodical analysis of lake water for the variation of tritium content may provide a basis to verify a number of critical facts as regards the source of recharge water and its movement in time and space. 4 BATHYMETRIC MAP BLUE LAKE, MT, GAMBIER — St erate a ere ies) Fig. 1. Bathynetsit map of the Blue Lake, with location of temperature and water sampling stations. Depths in metres. This map was originally constructed by the Department of Interior. b. Morphometry The morphometric data were calculated according to the procedure given by Hutchirison (1957) from a bathymetric map of the Blue Lake (Fig. 1), This was constructed by the Department of Interior in collaboration with the Horace Lamb Centre of the Flinders University of South Australia. Soundings were taken about 50 m apart, from which contours were drawn at 10 m intervals to a depth of 60 m, then at 5 m intervals to the bottom. For the purpose of calculation, the area at the maximum depth of 77 m was considered as zero. Morphometric terms (following Hutchinson, 1957) A, = area at cach contour in m?, by planimetry, Am = mean area between twa successive contours in m*, V, = volume between two successive contours in m*, PHYSICAL AND CHEMICAL. LIMNOLOGY OF THE BLUE LAKE 73 VP, = progressive volume between two successive contours in m*, by summing up the V,, terms, Z = depthinm, Zu = maximum depth in m, y = mean depth in m, Z, = depth of the deepest point in the lake below sea level in m, D, = development of volume, ratio of the mean to the maximum depth. Resulis The principal morphometric features of the lake are sel out in Table 1, TABLE 1 ee or ee Z Ay. 108 Ay, 108 | V;,-108 VP,.108 0 603 10 588 596 5,960 36,760 20 567 6578 5,780 30,800 30 544 556 5,560 25,020 40 517 530 6,300 19,460 50 482 500 5,000 14,160 60 431 457 4,570 9,160 65 278 404 2,020 4,590 70 270 324 1,620 2,570 76 79 175 81h 954 17 0 39 79 79 Zin Z Z, Dp, T7 61 61-6 0-79 —_—_———————————— eee The area of the lake at water level is 0-603 Km? (149 acres) and its volumetric capacity, 36-8 x 10° m* (8090 < 10° gallons; cf. Ward, 1941; 170 acres, and 8000 x 10° gallons). e. Temperature Measurement and results Measurements were taken at 5 stations (Fig. 1). The stations 0 and 5 were worked at more regular intervals than stations 1, 2 and 3, Vertical temperatures in situ were obtained from the readings of a Negretti and Zambra protected reversing thermometer. Overnight temperatures were not recorded. The results in this study (Fig. 2) are, however, considered to represent typical uveraves over a 24-hour Leviod Fig. 3 was constructed by interpolation to show the monthly yariation of surface water temperatures T,,. The air temperatures, T, for the same period are also included in the figure. Discussion As shown in Fig, 2, thermal stratification begins after September, becomes Fepaiineat in November and increases further in January, Until September, the ake is isothermal. It may be scen from Fig. 3 that the surface water temperature has a maximum in February, when the stratification probably is strongest. The maximum temperature gradient in January occurs between 15 and 35 m depth. The rate of fall in temperature is 0-24°C per metre, far less than Birge’s 74 TEMPERATURE “C/ METRE ~~ DEPTH, METRES TEMPERATURE “C — 30 40, 50! 6o 15 A. TAMULY TEMPERATURE °C —————— 6 7 18 3 20 24 22 NOVEMBE 67 JANUARY 6B wo rors eh FIG. 2 AVG AIR TEMPERATURE AVE SURFACE WATFR TEMP. S pe a 1 L A 1 DEC JAN FEB MAI 68 fe pe a R APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MONTHS = 38 87 87 8 0-10 0-05 0-01 NOVEMBER L 1 n 1 1 L r 3035 440 45 «8C DEPTH METRES Fig. 2. The variation of temperature with depth of the Blue Lake. Fig. 3. The seasonal varia- tion of surface tem- perature of the Blue Lake and mean air temperature, Fig, 4. The rate of change of temperature as a function of depth in the Blue Lake. PHYSICAL AND CHEMICAL LIMNOLOGY OTF THE BLUE LAKE 73 (1897) defined gradient of > 1°C per metre for a thermocline. Such a gentle thermal gradieut may be the result of the large D,, 0-79 in the Blue Lake. According to the Brénsted and Wesenberg-Lund (1911) concept, the plane of the thermocline lies at 20-25 m in November and shifts to 25-30 m in January (Fig. 4), The temperature falls at the rate of 0-16°C and 0-30°C per metre, respectively. Ertel (1954) proposed that the inflexion point of the thermal curve is dis- placed to a greater depth in the course of the heating period. This implies that the observed inflexion point at 20 m in November (Fig. 2) would be displaced to . 131 a depth of 20% /—=— = 29 metres ‘p JJ él in January which, in fact, is comparable with the depth of the plane of the thermocline at 25-30 m (Fig, 4). The mimbers 61 and 131 correspond to the eeperd time in days between 15th September, when the lake was isothermal, and 15th November and 25th January, respectively, dg, Energy-Budget Methods and related data The characteristic heat-terms (Welch, 1952) for the lake, which enter the following cquation (Hutchinson, 1957) were compnted from the present series of observed data and from some earlier radiation measurements: QO, = O, =Q.+ Q, +0, kde (2-1) Recorded data obtained from a Funk-type (1959) net radiometer exposed over grassland near Mount Gambier (C.8,1.R.O., Div, Soils, Adelaide, data for 1963-5) were corrected to the differences of temperature and albedo between lake and atmosphere to obtain net radiation, Q., above the lake surface, Q,, the change in the potential (stored) heat was estimated from the data in Table 1 and Fig. 2, “eo E was calculated from the Dalton-type equation (Sverdrup, 1937, 1951 E = 0-0024 (e, —c,) V ei + (22) and was then converted to Q,, the evaporative heat in the lake. e, and e, are yupour pressures at the surface water temperature T, and air temperature T,, respectively (Fig. 3). V stands for the wind speed, while the bulk aeradynamic covficient, 0:0024, was that obtained from a number of extensive studies on evaporation in lakes (Anderson et al., 1950, Budyko et al., 1954; U.S. Geological Survey, 1954a, 1958; Bruce and Rodgers, 1959; Webb, 1960). The quantity Q, or the sensible heat was obtained from the product of QO, and the Bowen ratio, & (Bowen, 1926): Qn = B°Qe - oe (2:3) Individual values of 8 for each month were calculated using the surface water temperature T,, air temperature T, (Fig. 3), and e, and e, at these temperatures, The barometric pressure, P, at Mount Gambier, was assumed to remain at LOO mb alae the year. The following equation was used to calculate 8 (SuLton, 1953): — fi. Ty — Ty P 9.4) alia | By — Eq | sa00 EN se The advective heat, Q,, was found by difference from (2-1), Local meteorological data were substituted for the quantities 'T, (e,) and Y in Equations (2:4) and (2-2), 76 A, TAMULY bl 7 = on a, le Poy , % ’ ~ i ‘ u \ é 5 ‘, / \ ‘ 7 A , \ i Ik | f \ { \ i i ssp of ‘ | \ f \ ( \ ? j \ q \ / 1 \ i \ / = ¢ i Fg yy ‘ ta / \ ) £ ay A ‘ < bgl \ ;} \ F) Los ‘ / ‘ / ui soa i 5 5 fe wh % ut Fig. 5. Heat content of the 1 ae ee, peroeeiae bine tO Blue Lake. NOV JAN MAR MAY JUL SEP ROY JAN MAR MAY JUL SEP NOY JAN MAR MAY £7 68 66 67 67 BB 66 87 67 68 MONTHS Or = net radiation Ot Schange i putential (stored) heat r +SED Qe =evapdoration heat Th =serisible teat Gy =aavective heat Tyan Gr fe ws be af 45100 \ as ALO eae clay | -= tal cr Fig. 6. The components of the energy budget of the Blue Lake. -20 - AuU SEP OCT NV DEC JAN FFA MAR APR May JUN JUL AUG SEP ST 67 6A o 87 MONTHS Results und discussion Monthly values of Q, in the lake were read from Fig. 5 which shows the total stored heat for the experimental period of 12 months. The energy-budget is graphically presented in Fig. 6. ‘The calculations provide a model energy-budget which is likely to he improved later with additional observational data. A radiation map of the lake would be useful if these studies are to be refined. Use of the empirical coefficient (0)-0024 in (2-2) is an assumption yet to be tested by experiment. It is found that the estimate of the lake evaporation E by equation (2:2) closely agrees with that computed from Class “A” evaporimeter pan results for Mount Gambier (Bureau of Meteorology Bulletin 44, 1961); for a period of 9 months (data available for Class “A” pan), these are 1225 mm and 1166 mm respectively. The advective component in Fig. 6 is significantly large at least for the summer months. A Q, of 150 cal. em.~? day~! amounts to an equivalent under- ground discharge of nearly 0:82 million m® of water per day, if the inflow is to change the lake temperature by 1°C; for a change of 2°C, the inflow would be 0:41 million m? a day. An advected subterranean flow at this rate may persist in the Blue Lake, It is reported (Ward, 1941) that a large outflow of freshwater to the sea of the order of 0-32-0-38 million m* a day occurs from the nearby springs at Ewen Ponds. PHYSICAL AND CHEMICAL LIMNOLOGY OF THE BLUE LAKE 77 e. Light Penetration A Secchi disk of 30 em diameter and twice coated with a flat white paint was used to study the transparency of the lake water. The mean of the depths of disappearance and reappearance of the disk observed under a shade was recorded as the depth of visibility, D. The extinction characteristics were then found from an empirical septa tunnhien (Poole and Atkins, 1925), by which the extinction coefficient k is defined by ed 9. k= > : ~~ (2°5) Lambert-Beer’s law + Seve, ... (2-6) o where [ = observed light intensity at depth d, and I, = incident light intensity, relates k to the concentration ¢ of any material that produces turbidity in the medium and, therefore, regulates the depth of visibility D. A derived form of Equation (2-6) k = (4-6/d’) — 0-03 ie ween, Parmer (2:7) is used to determine c¢ (Verduin, 1959). In general, d’, the depth of 1% surface light or the limit of the euphotic depth, is taken as equal to 3-4 times the Secchi disk transparency D (Riley, 1965). A comparable, but more precise value of d’ is derived from the Lambert law 1, = Ine-** , Where « is the depth and k the extinction coefficient, The value of d’ can also be determined by measuring 1% surface light with a submarine photometer. The value of 0-03 in the above equation is introduced to account for the extinction by pure water alone. Light observations with a Secchi disk provided useful information with regard to the optical properties of the lake water, The seasonal variation of the depth of visibility D, and hence that of the extinction coefficient k, indicated that an influx of additional material to Uhe lake oceurred just at the onsct of summer. The measurements of the two quantities given in Table 2 imply nearly a 50% reduction of D, increasing k from a value of 0- 1133 to 0-21.25 immediately after the blue coloration around mid-November, Later measurements tend to confirm that D increased gradually in keeping with the lake becoming progressively grey following the approach of autumm and winter. TABLE 2 Optical propertisa and euspensoids and dissolved material Tune Colour D k c Sept, 1967 Grey 14-5m0 01133 0°68 p.p.m. Novy. 1967 Bine 8- 0m 0-2126 0-30 p.pom, Jan, L968 Blue 12-5m - _— July 1968 | Grey 14-0m — _ D, depth of visibility; k, extinction cocfficient c, auspensoids and dissolyed material The extinction coefficient k determines the amount of light absorbed and scattered by water (k for pure water = 0-085) and by matter present in water; thus a k of 0:1133 in September implies an attenuation of the incident sunlight by about 31% by water and 69% by matter held in water; in November, for a k of 0.2125, the attenuation is altered to 16-5%. and 83-5%, respectively, 78 4A. TAMULY CHEMICAL LIMNOLOGY A number of chemical and related parameters were investigated both in the field and by bench analysis of water samples. The samples (1-2 litres) were collected in black, high density polycthylene containers, Certain interacting characteristics. are discussed together, with a view to understanding the lake’s chemistry in terms of simple equilibria. Methods a. Dissolved oxygen Water samples collected by a Nansen bottle were analysed in the field polarographically by a WPRL Dissolved Oxygen Meter A1672, using a wide-bore dropping, mercury electrode in conjunction with an Ag-AgC] standard ( Briggs and Knowles, 1958, 1961). The method has a standard deviation of 0:06 p.p.m., and the determinations at the sample pII are virtually free from chemical inter- ferences of a large number of cations and anions usually present in lake waters, The percent saturation of oxygen was calculated from the generally accepted formula, "(02 ) eat = 100 (02) / (2) sat 2 ~» ~ (31) where (02) = measured oxygen concentration, and (0s); = equilibrium oxygen concentration, The oxygen consumption in the lake waters was expressed in terms of Redfield’s (1942) apparent oxygen utilisation (A.O.U.) given by AOU, = (Oz) sat — (Ox). oh dab ie (3-2) The measured oxygen concentration (0.) was read directly off the Dissolved Oxygen Meter in p.p.m. Published tables (Moutgomery et al. 1964) were consulted to obtain (O:).a1 at the relevant temperature of water and 1013 mb pressure. A few oxygen measurements may have involved an element of error (10%) due to instrumental malfunction. b. Colloidal matter The technique of Tyndall scattering was applied io the detection of sub- stances present in the colloidal state, The intensity of light scattered from filtered samples (double Whatman No. 42) was measured in the laboratory in the arbitrary scale of a galvanometer; in this way, waters of different origin were compared with regard to the relative presence of scattering matter. The light scattering incasurements were made with an EEL Nephelometer in which a 12y-48w globe was used as a source of incident white light. The angular distribution of the scattered light at < 45°, < 90° and < 135° to an incident monochromatic beam (Hg-vapour lamp, A = 5160 A) was examined further, from another set of measurements on water samples with a Sofica Phato- Gonio Diffusometer. ce. pH A battery-operated Coleman pH-meter Model 37A was used in conjunction with a Tri-purpose combination electrode for the determination of pH, Samples were analysed soon after collection and at ambient room temperature. A weck’s collection of surface waters preceding 15th November, 1967 were also tested in order to follow closely the pH regime and its variation during the final stages of the luke’s transition from grey to a blue colour. PHYSICAL AND CIIEMICAL LIMNOLOGY OF THE BLUE LAKE 79 d, Major and minor elements Total solids were obtained by weighing dry matter left from evaporating aliquots of water samples (300 ml) in platinum dishes. A qualitative elemental survey of the lake water was made by emission spectrographic method of analysis in which a vormpact mixture of equal parts of the dry residue and graphite powder was bummed as anode by D.C, arc excitation, The speetrographic plate was then compared with a standard plate containing the spectral lines of the respective clements under consideration. Among the major cations in the lake water, only calcium was determined by flame photometry (EEL) of the lake water acidified to a pH of about 6, A small number of samples were analysed for traces of copper, cobalt and nickel by a combined technique of chelation (0-3% Na-diethyldithiocarbamate), solvent extraction (Methylisobutylketone, volume reduction 20X) and atomic absorption spectrophotometry. e. Dissolved organic matter Soluble organic matter of indeterminate composition occurs in all natural waters. These substances usually result from degradation of particulate organic matter, and also as metabolites and faecal products of living organisms. One specific class of organic compounds is known to exist in a chemically stable form as Huorescing substances in solution. The chemical route of formation of these substances is still obscure, although their presence in natural waters has been reported by several workers (Merker, 1931; Kalle, 1938, 1939, 1949, 1962; Hut chinson, 1957; Welch, 1952; Duursma, 1965). The development of cffective analytical techniques (extraction; chromato- graphy ) to isolate these substances non-destructively and to identify them remains as problematic as ever. The fluorescence characteristics, in particular, may be used to reveal al least in a qualitative manner the existence of organic malter in one form or another. With this assumption in yiew, initially an ultraviolet absorption spectrum (2000A-3000A) of the lake water was obtained on a Perkin- Elmer SP 800 spectraphotometer, Rather symptomatic information wus gathered on a relative scale by analysing filtered waters with an “Eppendort” Photometer for fluorescence characteristics at. the selected wavelengths of 3020A-3660A, AQ50A-4360A and 5460A, respectively. TABLE 3 Total solids in. p.m. Depth, m. September | October November 0 378 7 380 , a72 “" 16 — | -_ a 374 15 B80 — 37L - 20 : = —— 369 50 378 — b = a79 Ward (1941) May June Deeember Surface 413 394 360 _" 80 A, TAMULY Results and discussion The seasonal increment of ¢ (cf. Table 2) by about 0-1 p.p.m, appears to be due rather to soluble than solid matter of super-colloidal dimension (>10'A). The total solids in the lake water were found to be systematically less during the summer scason; the results in Table 3 agree with those given by Ward (1941). The present series of nephelometric measurements (EEL) hardly suggest a periodical increase of colloidal matter (size: 10A to 10*A) which may diffract sunlight and produce a blue colour in the lake water. The results, plotted in Fig. 7, include measurements from Stations 0 and 5 in September and November. 35 0 45 20 4Q , DEPTH, METRES 60) 70 Fig. 7. Light scattering of water samples as a function of depth of the Blue Lake, 80 The ratio of the scattering of light at < 45° and < 135° is a good measure of the size of macromolecules or polymers in solution (Debye, 1944). The method is very sensitive to sols containing molecules approaching the dimension of the wavelength of the light used, i.e., for molecular weights of = 10* or more. For molecules larger in length than 4/20, (1 = wavelength of the light), the angular scattering distribution becomes asymmetrical and, as a result, the ratio of I < 45°/I < 135° increases proportionally. The Sofica analysis of the lake water is presented in Table 4 relating the angular ratio with depth. The results on light scattering indicate both the presence of large molecules in solution and their concentration fluctuations in time and space, It is interesting to note that a large scattering ratio characterises the November samples from depths of 50 m and 15-20 m at Stations 5 and 0, respectively; a point-to-point PHYSICAL AND CHEMICAL LIMNOLOGY OF THE BLUE LAKE 81 TABLE 4 Angular Light Scattering I < 45°/I < 135° Stations 0 § Depth, m. September November November ‘is 0 8-0 | 9-3 7:6 10 12-5 6-0 7-2 q 15 wn 40-5 6-9 = 20 — 50-0 6-0 a 7 25 — — 10°60 30 4-4 5:8 10-5 40 6-8 9-Q 10-0 50 10-5 8-3 35-6 60 7-6 8-7 9:7 7 70 82 10°5 10-7 displacement of characteristic sols could have been induced by subsurface circu- lation beginning with a large advected flow into the lake in early summer. It is evident that only intensive sampling can assess finally the presence and distribu- tion of macromolecular sols in the lake water. A transitional low pH typified the surface waters between September and November. The weckly pH dropped from 8:45 on September Ist and fluctuated by about + 0-55-0-30 units until the waters attained an equilibrium pH of 8-15 by mid-November (Fig. 8). 1t is possible that perhaps the lowering and variation of the pI were caused by a variable discharge of underground water during the 6-8 weeks preceding complete equilibration in November. The surface values compare remarkably well with Ward’s (1941) measurements in summer and winter, viz. 8-15 and 8-45 to Ward’s 8-1 and 8-58. The pH decreases towards the bottom which constitutes a common feature in all lakes, As to the source of Fig. 8. pH of the Blue Lake SEP 7 SEP 18 SEP 29 OCT 2 OCT 10 OCTIG OCT29 NOWIS 67 67 67 67 67 67 7 67 WEEKS a2 A, TAMULY acidity of the bottom waters, a chemical analysis of the lake sediments may reveal the identity of the proton-donor, Lack of titration alkalinity data at present precludes a convincing explanation to the lowering of pH during summer; as suggested earlier, an incursion of relatively acidic groundwatcr may have altered the overall hydrogen ion concentration in the lake water completely. The water samples were examined, in the first instance, by arc-emission spectography. How- ever nothing significant could be detected in terms of differences. in concentrativn between the various elements present in the September (grey) and November (blue} samples. Inorganic analyses are routinely undertaken by the Engineering and Wattr Supply Department at Mount Gambier to ensure potability of Jake water for local corsumption, An official statement of an average inorganic analysis is reproduced in Table 5, It is also of interest to note that a consistent record of negative bac- terial counts confirms the absence of significant bacterial growth throughout the year. TABLE 5 Jnorganio analysis of Blue Lule waler (from BE, & W,8. Dept, records) CaG0, (present as HO0>) O8. ppm, MgC, (present as AC!07) 65 p.p.m. Mzg80, 16 p.p.m, NaCl — Ket 164 p.p.m. Miscellaneous salts 12 p.p.m, Total 366 p.p.m. The calcium content was found to vary between 30-34 p.p.m. (cf. Ward, 1941; Bayly and Williams, 1964) and the maximum centred around 50 m depth. The lake therefore appears to retain an equilibrium concentration (saturation) at all depths and irrespective of the time of the year. The temporary hardness: duc to carbonate species remained unchanged both in summer and winter (Ward, 1941). At an atmospheric CO,-content of 0-044% by volume at sea level, an equilibrium concentration of 30 p.p.m. Ca++ and 90 p.pm, IICO,- can exist in solution in water, Simple equilibria of the CO.-system in water (Buch, 1930) and the solubility data of CaCOs reveal that the ionic product [Ca++] [(CO.=] = 10-&+# tera [Ca++] = 30 p.p.m. and [HCO,;— + CO,~] = 3-21 mequiv/1 (Bayly and Williams, 1964) in the lake water is about one tenth of the solubility product of CaCO, (calcite), 10—***, at an average temperature of 15-20°C and §-2 pH. This fact alone excludes the probability of CaCO, precipitation under the lake’s pH and temperature conditions in the summer season (November to January obser- vations ). Chemical precipitation of CaCO, cun occur only if the pil is to exceed a value of 9, Colloidal CaCO, probably exists in the supersaturaled hard-water lakes of northern Germany (Ohle, 1934). There was no such observation of calcium or bicarbonate supersaturation in the Blue Lake's waters. Unlike cobalt, microgram quantities of copper and nickel present in the lake water varicd in concentration from September to November. Half of the copper was not available in November, likewise nickel was reduced. This reduction was caused not by fresh-water dilution, because neither a gain nor a loss in concen- tration was recorded for cobalt. Copper and nickel probably remained strongly hound te active organic solubles (Price, 1967) in the water and were not entirely PRYSICAL AND CHEMICAL LIMNOLOGY OF THE BLUE LAKE 83 stripped by the analytical method of artificial chelation, Such natural complexing agents in solution may resemble humic substances and its fractions in compo- sition, These substances may have their origin in the lake sediments (Kazakov, 1950; Krauskopf, 1956; Romankevitch, 1957; Degens et al., 1964; Palacas et al., 1966) or were carried ta the lake by groundwater. PERCENT OXYGEN SATURATION a a: a, a a = ee ben See | 10 20 . *iatiUARY ue 30 gr a «SEPTEMBER Fad *NOVEMBER > “JANUARY a ft 50}: - buf ef ' | Fig. 9. Oxygen content of the 70) Blue Lake water as a fune- | tion of depth. BO 1 DEPTH, METRES 42 Q 26 40 60 60 +1 0 = o o 7) 5 72 < + 3 ‘ ‘SEPTEMBER \ \JANUARY \WNovems eR Fig. 10, Apparent oxygen utiliza- tion as a funetion of depth of the Blue Lake. Some specific points from the results on percent oxygen saturation and the apparent oxygen utilisation are discussed here (Figs. 9, 10). It was observed that the change of the water colour in November coincided with an appreciable oxygen-deficit throughout the water column, and quite markedly so below the 50 m depth. The metalimnetic oxygen maximum at 20 m amounting to 140% supersaturation in the month of January could not have resulted from an outburst in primary production (photosynthesis), because in fact a lower pH (8°15) and a greater depth of visibility (13 m) were recorded in the lake water. According to the photosynthetic reaction: Photosynthetic reaction Ce. 0. 2 Me. ee ft ka ml nCat+ + nHCO; = nCaCOs + nCO, + nHaO = nCaCO,; + C,H.,0, + nO. the oxygen supersaturation was also not accompanied by a loss of calcium by carbonate precipitation. The systematic increase of oxygen up to 20 m (Fig. 9), 84 A. TAMULY followed by a rapid decrease in the metalimnion (Fig. 10), was probably induced jointly by the effect of turbulence and chemical oxidation of soluble matter during the summer stratification, By January, therefore, the oxygen profile assumed a typical form of a positive heterograde distribution (Ifutchinson, 1957), The U.Y, absorption spectrum of the lake water rendered little information, The photometric analyses on the “Eppendorf”? were quite instructive about the existence of fluorescing matter. The measurements were taken against a fluorescent standard cuvette and using a primary filter to isolate the selected wavelengths in conjunction with a secondary filter to prevent the unwanted scattered light from reaching the photomultiplier. Fluorescence from the samples was strongest at the 3020A-3660A wavcband, but gave a greatly reduced signal at 4050A-4350A and was practically negligible at 5460A, The relative intensities at 3020A-3660A were averaged for each depth and are plotted in Fig. 11. FLUORES SCERCE 1G 20 ac 4 st 60 70 bc so 1 t- T T T re | es ee eee | i, GREY s BLUE - ne ~~ NS 0 i _* = - . we se ss 20 ate te 30 Ne Sig or ~, E | att \ “ao ~ a a } Ww. oa 7 o al mains *S bs . yu, ow at, eed €¢ ae e c ~~ ; : =~ Bue Fig. 11. Relative fluoréscence of “a ’ water samples as a func- outy tion of depth of the Blue 0 Lake. The standard cuvette was used as a control for instrumental drift. There ure at present a number of basic difficulties in the calibration procedure. The fluorescing matter therefore could not be assessed in terms of concentration, The chemical synthesis of the humus-like fluorescing matter in the natural environment was investigated by Enders (1943) in great detail. Long ago, Kalle 1938-39) suggested that such fluorescing matter appeared to be one of the ecisive components in producing a blue colour in the ocean, These substances were known lo fluoresce light blue in the U.V. light, and were said to form, by a different route of condensation of methylglyoxal, the initial breakdown product of a carbohydrate (Enders, 1943; Kalle, 1962), The light sensitive matter in the lake water may resemble these substances in solution which would strongly chelate the number of transition elements; as they are also weakly acidic they would slightly, but effectively, increase the fiydirogenion concentration and undergo photooxidation and photoexcitation in the presence of oxygen and solar radiation with ten times more ultraviolet in the summer season, Ward (1941) reported in his article that, in fact, the lake water PHYSICAL AND CITEMICAL LIMNOLOGY OF TITE BLUE LAKE 8 absorbed four times more oxygen in simmer when subjected to a 4-hour per- manganate oxidation at room temperature. A blue Huorescence results from excitation at 30204-36604: the lake water was excited most at this bandwidth, The blue coloration appears to be more luminous than dull. Large masking particles are virtually absent in the lake water; the fluorescent blue, therefore, is more prominent than any other colour. Fluorescing matter may be brought to the lake in solution by groundwater, or released chemically at the lake mud-water interface (Mortimer, 1941-42). Chemical stratification of these substances seems to occur in the Blue Lake throughout the year (Fig. 11). The physico-chemical history of the lake changes qitite canviderably with a large inflow after September each year. The buildup of the soluble organic matter then reaches a threshold concentration in the upilinmion, after which the blueness in the luke becomes fully perceptible. ACKNOWLEDGMENTS Sincerest thanks are due to Professor J. R. M. Radok, The Flinders University of South Australia, and Professor J. W. Holmes, C.S.LK.O. Division of Sails and The Flinders University of South Australia. Assistance in the collection of feld data is acknowledged with thanks: Messrs M. W, Hughes and J. Forrest, C.S.ER.0. Division of Soils; B, [Iughes and PD. PD. Fisher, The Iorace Lamb Centre, The Flinders University of South Australia: Engineering and Water Supply Department, Government of South Australia; The Bureau of Meteorology. Adelaide. Thanks are also due to Messrs R. M. McKenzic, C.S,1.2.0. Division of Soils, D. N. Cramond, Department of Physical and Mmorganie Chemistry, Univer- sity of Adelaide, and Dr D-_ |. Greenland, Waite Institute, Adelaide for assistance in laboratory work and provision of analytical facilities. REFERENCES Annenson. BE. R., Awnenson, J, J., and Manciano, J. ]., 1950. A review of evaporation theory and development of instrumentation, Lab, Rep, U.S, Navy Electron. No. 159. Bayiy. I, A. B.. and Wittiams, W. D., 1964. Chemical and biological observations on some volcsatic lakes in the south-east of South Australia, Aust. J. mar, Preshwat. Res, 15 (2), 23-152. Braney, H. J.., 1957, Mount Gambier Water Supply, Engineering and Water Supply Depart- ment, Government of South Australia Rep. No, PD, 7, Brace, E, A,, 1897. Plankton studies on Luke Mendota. TT The: erustacea from the plankton from July, 1894, to December, 1896, Tvans, Wis, Acad, Sci, Arts Lett, 11, 274-448, Bowen, I. §., 1926. The ratio of heat losses by conduction and by evaporation from any water surface, Phys. Rey., 27, 779-787 Brccs, R., and Kwownes, G., 1958. Use of the wide-bore dropping-mercury electrode for long-period recording of concentration of diysolved oxygen, Analyst, 83. 804-311 Birces, R., and Knowrss, G., 1961, Developments in the use of the wide-bore dropping- mereury electrode for determining ‘lisyolved oxygen and oxygen in gases, Analyst, 86, 603-608, Bnésstep, J. N., and Wesenserc-Lunp, C., 1911. Chemisch-physikalisehe Untersuchuneen der danischen Gewasser nebst Remerkungen iiber ihre Bedeutung fiir wascre Auffassung der Temporalvariationen, Int, Rey. Hydrabiol,, 4, 951-290, 437-492, Bruce, |. P., and Roncens, G. K., 1959, Water balance of the Great Lukes Syulean, Symp. Great Lakes Basin, Chicago, AAAS publication No. 71, 41-69, Washington, D.C, Bucs. AS 1930. Die Kohlensiurefaktoreon des Mecrwassers I. Rapp, Cons, Explor, Mer. 67. 5-88, Buprxo, M, lL, Brnyvuanp, T; G., and Zunewox, L. I, 1954 Izv, Akad. Nauk. SSSR, Ser. Geogr, No. 3, 17-41. Tutetms dt, 1961, Evaporation in Australia, The Bureau of Meteorology, Commonwealth of Australia, Melbourne, Danve, P,. 1944, Light scattering in solutions, J. appl. Mhys:. 15, 338-349. 46 A. TAMULY Decens, KE, T,, Revren. J. H., and Suaw, K. N. F., 1964. Biological compounds in offshore California sediments and sea waters, Geochim, cosmochim, Acta, 28, 45-66, Duursma, E. K., 1965, The Dissolved Organic Constituents in Sea Water. 433-475, in Chemical Oceymography Vol 1, ed. J. P. Riley and G. Skirrow, Academic Press, London and New Yark. Envers, C,, 1943, Wie entsteht der Humus in der Natur? Die Chemie, 56, 281. Eyrels Et ws 1954. Theorie der thermisehen Sprungschicht in Seen, Acta hydrophys., 1. Fenn, C., 1921, The craters and lakes of Mount Gambier, South Australia, Trans. R. Soc. $. Aust,, 45, 169-205. Funr, J. P., 1959, Improved polythene-shielded net radiometer, J. scient, Instrum., 36, 267-270, Hurcninson, G.. E., 1957. A Treatise on Linmology, Vol. 1, J. Wiley, New York, Karur, K,, 1938-9, Die Farbe des Meeres, Rapp. Cons. Explor, Mer., 109, 98-105. Kairie, K., 1949, Fluoreszenz und Gelbstoff im Buttnischen und Finnischen Meerhusen, Dr, hiydtogr. Z., 2 (4), 117-124. Kauie, K., 1962. Uber die yveliisten organischen Komponenten im: Meerwasyer, Kieler Meer- forsch., 18,, 128-131. Kazaxoy, E. Ll, 1950, Genesis and. chemical nature of sweet water sapropels, Trudy Inst. voryuch. Iskop., 2, 253-266, Krauskorr, K, B., 1936, Factors controlling the concentration of thirteen rare metus iu ste water, Geochim. cosmochini. Acta, 9, 1-34, Maireun, E., 1931. Die Fluoreszenz der von PAhanzen und Tieron bewohnten Gewssser und ihre verminderte Liehtdurchlissigkeit, Die Naturwissenschatten, 19 (21), 433-435. Montcomery, H. A. C..'THom, N.S, and Cockpunn, A,, 1964. Determination of dissolved oxygen by the Wiukler anethod and the solubility of oxygen in pure water andl scawuter, J. appl. Chem, 14, 280-296. Moutimmenr, GC. H., 1941-2, The exchange of disselved substances between mucl ancl water in lakes, J. Eool.. 29, 280-329; 30. 147-201, One. W.. 1934, Chemische und physikalisehe Untersychungen nord-deutscher Seen, Arch. Hydrohiol., 26, 386-464, 584-658. Paracas, J. G., Swanson, V. E., and Moone, GC. W., 1986. Orvanic gunchmistry pf three north Pacific deep-sea sediment samples, Prof. Pap. U.S. geol. ‘Surv., 550-C, 102-108. VYooie, H, H., and Arxins, W. R. G., 1929. Photoelectric measurements of submarine illami- nation throughout the year, J. mar, biol. Ass. U.K., 16, 297-334, Prick, NY He Pia Geochemical observations on manganesé-iron oxide nodules, Mar. Geol., 5, 511-538. Reviecp, A. C., 1942. The processes determining the concéntration of oxygen, pliosphate and! other organic derivatives within the depth of the Atlantic Ocean, Pap. phys, Oceanogr., . No. 2. unr J P, ed, 1965, Chemical Oceanography, Vol, 1, Academic Press, London and New ark. Rowankeviren, E. A. 1957. The organic matter in core-samples of bottom. sediments in the north-western part of the Pacific Qcean (cast of Kamchatka), Dokl. Akad, Nauk. SSSR, 116 (3), 447-450, Surron, O. G., 1953. Mierameteorology, McGraw-Hill, New York. Svexoxuy, H. U., 1937. Ou the evaporation from the oceans, J. muir. Res, 1 (1), 5-14. 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THE STRATIGRAPHIC DISTRIBUTION OF THE EDIACARA FAUNA IN AUSTRALIA BY MARY WADE* Summary The uppermost Precambrian Ediacara fauna has been found in almost continuous outcrops along the west flank of the Flinders Ranges, from near Hawker to Mt, Scott Range 140 km north. All occurrences are stratigraphically low in the upper member of the Pound Quartzite. In parts of this region erosion prior to deposition of the Parachilna Formation has removed 500 m or more of the upper member; the entire upper member was eroded prior to the deposition of the Parachilna Formation or the Lower Cambrian Wilkawillina Limestone, in the ranges on the east flank. Trace fossils, Plagiogmus and probable Rusophycus, indicate a lowest Cambrian age for the Parachilna Formation, which is overlain by the Wilkawillina Limestone or its equivalent the Ajax Limestone. THE STRATIGRAPHIC DISTRIBUTION OF THE EDIACARA FAUNA IN AUSTRALIA by Mary Wade” ABSTRACT The: uppetmost Precambrian Ediacara fauna has been found in almost continuons outcrops along the west flank of the Flinders Ranges. from near Hawker to ME. Scott Range 140 km north, All oceurrences are stratigraphically low in the upper member of the Pound Quartzite, In parts of this region erosion prior to deposition of the Parachilna Formation has remioved 500 m or miore of the upper member; the entire upper member was. eroded prior to the depasition of the ParachiIna Formation or the Lower Cambrian Wilkawillina Limestone. in the ranges on the east flank, ‘[race fossils, Plagiogmus and probable Rusuphycua, indicate a lowest Cambrian age for the Parachilna Formation which is overlain by the Wilkawillina Litiestone or tts. equivalent the Ajax Limestone. INTRODUCTION The rich Precambrian fauna discovered near the top of the Pound Quartzite at Ediacara Range by Sprigg (1947, 1949) was uugmented by the collections of Mitcham and Flounders (Glaessner, 1955 et seq.) and later workers. These dis- coveries and the failure ta find fossils at other levels in the Precambrian at Ediacara triggered fruitless searches concentrated on the top of this formation elsewhere. Only in the area of outerop closest lo Ediacara Range, Red Range. Beltana, was a small fossiliterous outcrop revealed; this was 180 in below the top of the Pound Quartzite, a much greater distance than at Ediacara, and in a much thicker sequence. The stratigraphic relationships of these (wo isolated areas remained uncertain. The study of the preservation of the soft bodicd fauna (Wade, 1968) brought out the fact that requirements for preservation were not particularly stringent, The fauna could be preserved anywhere that sediments which had finally been deposited without reworking could be found. Such an environment was ascribed ta the Ediacara Range deposit on independent sedimentary evidence by Goldring and Curnow (1967). The conditions required for the exposure of fossils were either that the rocks were nitnrally faggy, or that the fossils were sufficiently tough und large to cause a weakness in a massive rock where sand-erains had been prevented from interlocking, so that the rack parted along the site of the fossil during weathering. Acvordingly a new inyestigation was launched, which umeentrated on finding suitable beds. It was immediately successful, The present paper records the stratigraphic position and distribution of the Ediacara fauna within the area shown in Fig. 2. Fig. 2 shows the outcrop of the Pound Quartzite in the area outlined in Fig, L and indicates the 22 sections examined in the course of this work. Areas not yct examined include the thickest rae Se of the Pound Qnartzite, the northeast of the Northern Flinders janges. PREVIOUS WORK Reference to the Pound Quartzite is found in many of the works of Mawson who measured sections at Ltalowie Gorge and Campbell's Bald Hill Mange { Mawson, 1937), defined the formation (Mawson, 1938), gave the earliest deserip- tion of the two members into which the formation és still informally divided (Mawson, 1911), and preliminarily mapped most of the Central Flinders Raviges * Geology Dept.. University of Adelaide. Trans. A. Sac, §, Aust. (1970), Vol. 94. M. WADE Alice Springse ~y St SOUTH AUSTRALIA Adelaide » + fossil tocalities Upper Marinoan sedimentation = Middle " 4" Fig. 1. Areas of Late Precambrian sedimentation showing localities where fossils of the Ediacara fauna have been discovered. Boxed area, within the Flinders Ranges, sec Fig. 2; “x”? Punkerri Hills; “y” a few km E of Deep Well Homestead SSE of Alice Springs; “z’ Fowlers Gap Beds underlying Lintiss Vale Beds a few km NW of Acacia ny Homestead, NNE of Broken Hill. (Mainly after Thomson, 1969a, and Webby, 1970, DISTRIBUTION OF EDIACARA FAUNA 89 ! Beltana y ames Na” Randeithe Es Lookout eltana Hill Patawarta \ oayres Range x 2 Nilpena 3 HiNS Gat Michael Tago SGrean Well — ar 13 is \ / FAULTS @ DiaPIRS I SECTIONS TRAVERSED, THOSE MEASURED, 1-1} EE] POUND. QUARTZITE (undifferentiated in i northeast, & upper Brachina Gorge member, elsewhere) rt lower member ? Oraparinna ag Bunyeroo Gorges ae YW Diapir it) Pil ' Fig, 2, Outcrop of Pound Quartzite showing sections searched for fossils: fossils in situ have been obtained from 1-3, 5-11; defi- nitely _fossiliferous float from 13 and 17, Nilpena Hills and Patawarta Gap, and probably fossil- iferous float from £} Puttapa Spring, 12, e Diapirs within the | area are shown in black. 21g @alack Jack Range PSugarioa on M. WADE (Mawson, 1942). Additional references may be found in Teesdale-Smith (1959). There is considerable difficulty in reconciling some of the thicknesses obtained in this carly work with later data. Campana (1958) provided a number of structural sections across the Northern Flinders Ranges but omitted the thicknesses of beds. Thicknesses ure provided by Thomson (1969b) in interesting diagrams of the facies relationships but the diagrams are of too small a scale to allow precise geographic lovation, ar to show structure. Modem siratigraphic work at Ediacara commenced with Glacssner and Daily (1959) and was continued by Nixun (1963), and by Goldring and Curnow (1967) on the sediments. Goldring and Curnow conyincingly demonstrated an unconformity between the Pound Quartzite and the overlying Parachilna Forma- tion al Ediacara Range, though their paper was not cited by Leeson (1970) who adhered to the view that there was nu significant break and Segnit’s. report ee of a disconformity in this position was wroug. Meanwhile Dalgarno (1962, 1964 and Dalgarno and Johnson (1962, 1964) in defining and discussing the Parachilna Formation in the main Flinders Ranges had already shown a regional uncon- formily in the sane position, which may he equated with that at Ediacara, The first large-scale attempt to systematize the description aud naming of beds in the Adelaide Geosyncline was carried out by Daily (1956) on the Cam- brian. Thomson ef al. (1964) similarly established a regional nomenclature for the Precambrian. The most recent review is that of Thorson (1969b), Since the 1980's the South Australian Geological Survey has been issuing taps of parts of the relevant area on the 1:63,360 scale, More recently this data and that gathered by later work has been distilled into 3 shects of the 1:250,000 geologic map series. From $ to N these are; Orroroo (Binks et al., 1968), Para- chilna (Dalgarno aud Johnson, 1966) and Copley. The last is an unpublished preliminary version displayed in MS, The Parachilna 1:250,000 sheet was the first to record the distribution of the lower and upper members of the Pound Quiurt- vite. This example was followed in the 1:63,360 map series but regrettably not in the Orrorco 1:250,000 sheet, nor, as yet, in the Copley shect, Reports of tayesti- gations accompany some mup sheets: Arrowie (Horwitz, 1962}, Blinman Dome Pepectal series; Coats, 1964a), Marree (Forbes. 1966), Beltana (Leeson, 1970), or concer other projects such as the hydrology of Frome Embayment (Ker, 1966) which assembled littlh--known subsurface data. STRATIGRAIIPY The Pound Quartzite is the youngest formation in the Adelaide Geosyneline to which the age “Marinoan” has beeu applied (Thomsyun et al. 1964; Thomson, 1969b), If it is intended that Marinoan reach to the base of the Cambrian (Thomson, 1986), however, u subsiduary twpe area where the rocks do not terminate in an unconformity should be sought. All beds containing elements of the Ediacara fauna have been pluced in the Upper Marinoan Epoch (Fig, 1, +), Within the Adelaide Geosyncline the leds deposited during the Marinoan have already been recognized as susceptible of a 3-fold subdivision (Thamson et al, 1964; Thomson 1969b, pp. 68-79, figs, 22, 27). This subdivision appears likely ta be widely applicable. The oldest or Lower Marinoan sediments are influenced by the third and last phase of Precambrian glaciation which has been used for correlation with northwest New South Wales (Webby, 1970), and is possibly correlative to the last phase of gluciution in the East Kimberleys. which is overlain by marine shales currently dated at 665 =45 m.y. (Compston and Arriens, 1968), The Lower Marinoan sediments of the Adelaide Geosyacline are part of the Umberatana Group which also includes all DISTRIBUTION OF EDIACARA FAUNA o bot PARACHILNA FORMATION \€ POUND LE upper B page Pf 7 fneiriher —<— Ediacara faung = sy lower yt SS ee 4 JQUARTZITE [7% Py AE member [its 4{—3 i es 9 a Cie) : ye ® 1 it 7 ha . Vertical ——200m n WONOKA (9 5 FORMATION Horizontal ———1 0 km Fig. 3, Sections 1-1] as named on fig, 2, Only the central portion of section 1 was measured, the total thickness is conservative. the Sturtian glacial and inter-glacial beds. Stromatolites are the only known fossils, The remainder of the Marinoan sediments are the Lower and Upper Wilpena Group scdiments (Thomson, 1969b, fig. 27) which may be regarded Seipecsitely as Middle and Upper Marinoan. The trace fossil Bunyerichnus dalgarnoi Glaessner (1969) was described from the Middle Marinoan of Bunyeroo Gorge but no other fossils are known. The Upper Marinoan consists of the Bunyeroo and Wonoka Formations and the Pound Quartzite which alone has produced animal fossils. These are of such variety and size that a long history of development must lie in older sediments. Fig. 1 shows the distribution of sediments of Middle and Upper Marinoan age (after Thomson, 1969b, fig. 27, Webby, 1970) and known fossil localities of the Upper Marinoan, The area marked “?” is the Frome Embayment of Mesozoic thickoess t— wis wom WN F | C f (17 aig Hm Fig. 4, Gencralized sketches of the outcrop from the top of the lower member, Pound Quart- zite, through the fossil beds. Trne dips and thicknesses are shown. A. Brachina Gorge. B, Bunyeroo Gorge. C. Muyo Gorge, 1, Top of lower member. 2. Unfossiliferous basal beds of upper member, 3, Lowest fossiliferous bed. 4. Unfossiliferous intercalation. 5, Upper fine-grained fossiliferous bed. 6. Fossiliferous, fine- to coarse-grained, white sandstones. 7, White sandstones of the crass-stratified to flat stratified facies. Slump rolls have been observed in 5-7 where diagrammatically indicated, The horizontal lines helow 3, 5, G indicate approximately the position of fossiliferous becis. 42 M. WADE to Recent age which is known from bore data (Ker, 1966) to be underlain by Precambrian and Cambrian rocks in N-S trending blocks, like these exposed on its east and west margins, Detail on ihe correlation of possible Adelaide System rocks is lacking. The Pound Quartzite This formation occurs between approximately 30° and 32°33’S latitude. It rims many synclinal and basinal structures in the Northern and Sonthern Flinders Ranges but is restricted to the Aanks of the Central Flinders Ranges (Fig. 2) where uplift and deep erosion bas exposed Sturtiun rocks and large diapiric cares (Mawson, 1942; Coats, 1964a; algarno and Johnson, 1966), mediately prior to the deposition of the Pound Quartzite, fine-grained carbonate-rich sediments were deposited aver the area. These rocks are known as the Wonoka Formation (Dalgarno and Johnson, 1964) and are usually grey to brown or red siltstones and shales with bands of limestone but occasionally dolomite or limestone predominate, ‘The base of the lower, or red, member of the Pound Quartzite indicates an abrupt regional change to haematitic, felspathic sandstones (Fig. 3), usually through non-caleareous, red siltstones. The member is dominantly medium- to fine-prained, with ferruginous coatings on the grains in most beds, though some included sandstones are orthoquartzitic; it contains minor amounts of clayey siltstones and a very few grits; small-scale cross-bedding is dominant but current- swept, Hat bedding planes also occur; ripple-marks are cormmon; a few bedding nes reveal a suitable lithology for the preservation of fossils but only rarely ne possible trails been found. A basal conglomerate occurs south of the Beltana Diapir in Red Range (Leeson, 1970), The upper, or white, member consists of clean, coarsc to medium-grained felspathic sandstones, with rare fine sediments. For the most part beds are rather massive and cross-stratified to flat-stratified (Goldring and Curyow, 1967). Slump rolls are common in some beds, as are mudflake conglomerates, cut-and-fill scours and ripple-marks, Grit bands are rare; conglomerate bands oceur adjacent ter Mucatoona Diapir. For the most part reworking during deposition has removed any ferrnginous coatings from grains but at a height of about 16-80 m ahove the base in the west Hank of the Flinders Ranges, red beds are included in a suh- stantially fine-grained deposit which extends for 145 km N-S, from the south branch of Green Well Creck to Black Jack Range, south of Hawker. A great deal of this is very fine-grained sandstone and minor siltstones and much of it is fussiliferous, The thickness of the fine-graincd heds varies from 7-112 m, largely according to how much barren sandstone is interbedded. The barren sandstones may be relatively fine and even-bedded (Mayo Gorge, Bunyrroo Gorge; Figs. 3 (2.5); 40,8); mud-pellet conglomerate, coarse sandstone, and smal) “slump rolls” (Bruchina Gorge, Figs. 3 (6), 4A); or slump rolls up to 2-3 m thick and normal, hedded sandstones (Parachina Gorge, Fig. 3 (7)). Evidence of slumping and/or scouring is recurrent wherevee sections have becn examined. Fossils are known in almost continuous outerops from Green Well Creek to Yappala Range just WNW of Hawker. Isolated From these almost continuous outerops are beds with fossils at Red Range, Edicara Range and Mt, Seott Range. All these beds accur low in the upper member of the Pound Quartzite, and they are correlated as a datum plane in Fig. 3, The fine-grained sediments are almust exclusively red beds from Mt. Scott Range in the north to south ef Brachine Gorge but the lower portion is whitish samlstone at Bunyeroo Gorge and south (Fig, 4, A-C). DISTRIBUTION OF EDIACARA FAUNA a9 The picture of the Pound Quartzite as an uncomplicated, two-member formation is over-simplified, though there are only minor deviations from this norm in the area of the Parachilna 1;25),000 shect and adjacent parts of the Orroroo 1:250,000 sheet to the south. These are: 1. Intermittent orthoquartzitic sandstones in the lawer member; particulurly thick beds are seen at Green Well Creek on the west Hank and on the cast flank at Wilkawillina Gorge, near Oraparinna Diapir. 2, The fine beds near the base of the upper member on the west flank. 3. Light maroon, haematitic sandstones occurring intermittently in the upper member particularly in Yappala Range and around Parachilna Gorge- North of 30°57’ on the west Hank of the ranges, the lower sediments become more sandy between Nilpena Hills and Green Well Creek on the south, and Red Range on the north. Section 9 (Fig. 3) is hased upon thicknesses measured by Major (unpublished thesis, 1964) along the creek next south of Red Range water- bore, and in « direct line east. He did not make a large-scale subdivision of the Pound Quartzite but his data suggested, and further field study has confirmed, that the section could be divided into three units on the basis of upwardly decreasing frequency of red beds. These three units were, from the base: 140 m of haematitic, felspathic sandstones lithologically characteristic of the lower member; 248 m of interbedded. haematitic and orthoquartzitic sandstones: 257 m of mainly orthoquartziti¢ sandstones with minor ted beds. Comparison of thick- nesses with section § (Fig. 3) served ta sugyest that the two lower units at Red Range, together, are equivalent to the lower member te the south, and this was confirmed by the position of the fossiliferous bed. The outcrop at Red Range is duplicated across a N-S strike fault (Leeson, in Leeson and Nixon, 1966; Leeson, 1970, figs. 3, 4) but contrary to both publications the lower member as well as the upper outcrops west of the strike Fault, though its base is truncated. The fossil bed is thinner and less rich in the eastern section than in the western; only the epichnial groove Form B (Glaessner, 1969), has been recovered cast of the fault, while fossils listed in Table 1 have been found in the western outcrop. There the fossils occur through 11m, in comparison with 3 m in the eastern outcrop where beds lack the finer sediment-sizes, Fig. 3 (9) is composite to the extent that the fossil beds have been shown as 11 m thick though the overall measurements have been taken from the eastern outcrop, As far as can be judged from pacing the sections, the thickness of the upper member is approximately the same in the western and eastern outcrops; the dip is 70°W in the west and 35°W in the east. The function of lower and upper members is extremely weathered and the boun- dary is not definite in the west section but from 180-225 m of the lower member are present, Leeson (1970, pp. 27, 28) described a section across Red Range but did not say where it was measured. Although he also subdivided the Pound Quartzite into three units, the Jower two of which are equivalent to the lower member, his thicknesses cannot be reconciled with those of Major. This boundary between lower and upper member (Leeson, jn Leeson and Nixon, 1968) accurs in the field precisely where it would be placed on Major's data, Leesan describes the base of the lower member as intertonguing with the Wonoka Formation, and also as being conglomeratic at the north end of Ked Range, adjacent ta Beltarut Diapir. He could not reeognize any pebbles from the diapir in his sediments but very little of the diapiric material is of striking lithology. Threefold sequences like that at Red Range are also found at Randell T.ook- out in Edicara Range and Mt. Seott Range, and, according to Leeson (1970), are general for the arca of the Beltana 1:63,360 map. The sections measured at Randell Lookout by Major (unpublished thesis, 1964) and by Daily (1956) at Mt. Scott ny M. WADE Range are used in Fig. 3 (10, 11). Neither author attempted a major sub-division of the Pound Quartzite. When correlated with cach other and with the fossil beds this threefold sequence fils the regional picture, as J.eeson (1970) has said, pro- vided the lower two units are corrclated with the “lower, red member" of the sections to the south (Fig. 3 (1-8)), The fossil beds thus provide confirmation of the lithologie correlation in this region though elsewhere on the western flank the stratigraphic position has been used to show that the fossil beds form one band only. Leeson (1970, pp. 27, 28) also published a sectinn through the Pound Quurtzite at Randell Lookout which is not in close agreement with that of Major excep for the overall thickness, he topographically highest ridges in Red Range and Randell T.ookont sections are white sandstones among the red and white sandstones. They replace the white member as the chief scurp-forming ridges here, thongh not at Mt. James as is clear from Goldring and Curnow (1967). At Mt. Scott Range, in a similar set of three Jithologic types, the chief scarp-Forming bed is again a white sandstone among the red and white sandstones, and once more the fossil beds occur in maroon sandstones and silts about 60-80 m above the base of the third unit (the dominantly white sandstones). This local variution points ta an inde- pendent movement involving the Beltana Diapir complex, which preceeded the regional shallowing of the deposition basin that terrminaled deposiliog af the lower member. SRCTIONS EXAMINED The Western Flank The type area of the Pound Quastzite, Wilpena Pound itself, has been investi- gated near Wilpena Chalet on the east side of the entry (Fig. 3 (4)) but here the bedding planes are offen current-swept, and massive to coarsely laminated sandstones form the lower part of the upper member; indeed, it is massive throughout. It is the only section on the west fank where the fine-grained beds which are ustially fossiliferous are known to be completely replaced by coarse scdiments; though the sediments at Nilpena Hills tend this way, a fuw clayey laminae were present there. Sections which have heen systematically scarched for fossils have been plotted on Fig, 2 (1-21) but save for Wilpena Chalet, section 4, unfossiliferous sections are not ilustrated in Fig. 3 for they have not been measured in whole or in part as have those that are illustrated. Twa of these unmeasured sections have yielded fossililferous float but nothing in situ: 13, Nilpena Hills, 27 km W of Green Well Creek, am 17, Patawarta Gap on the east flank of the Flinders Ranges, 25 km E by N of Green Well Creek. Possibly foxsilifernus Moat was found at 12, Pullapa Spring, At 8, Green Well Creek, and 7, Parachilna Gorge, a more gradational change from lower to upper member is seen than that found to the south, From the commencement of dominantly ortho- quartzilic sandstone deposition, it is interlayered with haematitic siltstones and sandstones for the Brst 4:5 m at Green Well Creek and the first 15m at Parachilna Gorge. As the fossiliferous beds can be traced from the south te Green Well Creek the rather massive orthoquartvites helow the trausitional, banded bed there mnst represent the top of the lower member (Fig. 3 (8)), though they were mupped as belonging to the upper member whichis covered by ontwash on the north side of the creek, These massive orthoquartzites occur so high in the lower member that they can scarcely represent the sandstones associated with the Beltana Diapir (pp. 93. $4). There are nearer small diapirs (Fig. 2), Nilpena and Green- well Diapirs being closest and both associated with Nuccaleena Fault (Leeson, 1970). Facies changes between Nuccaleena and Greenwell Faults and adjacent to Greenwell Diapir (Leeson, 1970, fiz. 6) show that this diapir was moving in DISTRIBUTION OF EDIACAKA FAUNA bs] late Lower and Middle Marinoan times, while the recorded movement of Nilpena Diapir was post Lower Cambrian. They outcrop on Nuccaleena Dome, a much larger structure which Leeson (1970) considers likely to overlio a large diapiric core OF which they are apophyses. At Parechilna Gorge some bands of haematitie sandstone are preient throughout the lower three-quarters of the upper member; these. and interbedded white sandstones, are hoth rather sugary in texture and often become friable when weathered. In these last two characters the white sandstones of Green Well Creek and Nilpena Hills are similar. The wpper one quarter of the upper member at Parachilna Corge is as indurated and massive as is usual in the upper meniber further south, and the lower three-quarters is also massive (except for the fossiliferous heds) only a few km to the south (pers. comm. KR. F. Harris), The fossil beds ut Brachina Gorge (Fig. 3 (6); table 1) are the richest part of the new outcrop but otherwise quite typical, and are detailed as an example (Fig. 4A), Total thickness of the lower member here is 340 m, and of the upper member 440 m. The fossiliferous section at Brachina Gorge begins 71 m above the base of dhe upper member wad cansists of the beds numbered 3-6 in Fig, 4A: (3) LO mi silty, fine sandstone with miner amoumits of clay, Most is maroon but some laminae ave slightly greenish white. (4) 3-3 m dense, massive, white sandstone with mud pellets concentrated near the base. To the south of a transverse fault which is hidden by seree cxeept where it intersects Brachina Creck, this while sandstone is less massive. less well exposed. and possibly thinner ut is still the only totally unfossiliferous subdivision of the “fossiliferous” beds, (5) $ m silty, clayey sandstone, maroon coloured, with slump rolls of coarser maroon sandstone in the upper 1 m. (6) At Jeast 3 m dense, massive white sandstone with slump ralls ange occasional hedding planes that bear Dickinsonia fairly commonly and fess often other fossils similarly “resistant” enough (Wade, 1968) not to haye vallapsed or decayed prior to the setting ef the enclosing rock. The same lithology continues ubove (Fig. 4A (7)) but without fossils, althongh very rare bedding planes are found with surfaces whose smonthness indicates that the sand forming them was deposited against a fine-grained surface (Wade, 1968). These could preserve fossils but are very rare; their total exposed area is only a few square mnetres, No fossils are known. This same rarity prevails in the massive beds at every section examined. The cross-stratified to Aat-stratified facies of the Pound Quartzite is nomnnally depusited under too rigorous conditions of sediment- transport to preserve a snft-badied fauna. On smne rock faces even srnonth surfaces showed evidence of scdiment-transpart which would have destroyed soft bodies; Wilpena Chalct and Patawarta Gap sections are samples of this—but nevertheless a piece of float with faecal pellets. on it was found in the creek al Patawarta Gap, At Bunyeroo Gorge (Figs. 3 (5), 4B) the fossil beds contain considerable fine-grained white sandstone which is largely barren but has fossiliferous layers intermittently init. Fine-grained maroon sandstones to siltstones occur higher in the section, and the Jower 6 m of enarser sandstones above the Gne-grained sediments parts on bedding planes which are occasionally fossiliferous, The beds continue to the south, becoming coarser and unfossiliferous to the SSE in Wilpena Pound. They thicken considerably hut remain fossiliferous to the SSW, where the greatest thickness of the fossil beds (112 m) was moasured at Mayo Garge, where Hookina Creek cuts through Elder Range, 15 km N of Hawker. This section is complicated by a number of faults atl the lower part of the upper member is repeated four times. The most informative section (Figs. 3 (2), 40) is In the block between faults F2 and FS, 1t is rather sparsely fossilifecous except near the top of the lower fossiliferous bed where the cpichnial groove Form B is cammon 96 M. WADE an] medusolds are rare, In the same stratigraphic position between faults F3 and F4 quite arch fauna wus found (Table 1). The hase of the section was absent from this block. The more westerly section at Hells Gate (Fig. 3 (3)) is probably not as poorly fossiliferous as the record of only Form B would suggest. It is deeply weathered and leached white now, though it may have been partly red-beds prior to weathering, It docs not part cleanly; its very Houry texture indicates that chemically destructible, presumably clayey, material was present throughout the laminated, fine-grained silty sandstone. The Yappala Range section (Vigs. 2: 3(1)), on the other hand, is really sparsely fossiliferous. As in Mayo and Bunyerou Corges, the fossiliterous beds are largely white, Jaminated sandstone with some maroon siltstone near the top. The fine-grained beds here are closer to the base of the uppet member than in any other section, only 16 m above the lower member. The section at Black Jack Range { Fig. 2 (21)) may yet prove to be sparsely fossiliferous; a short distance ubove its base, the upper member contains mainly very fine-grained maroon and white sandstones in a limited exposure. Chace and Druid Ranges to the northeast voutuin a similar sequence but it is badly weathered and badly cxposed at sections 19 and 20, as on Mawson's line of section (1941), As the sequences are Wraceable into those at Yappala Range and Black Jack Range, respectively, they must be considered ag potentially fossiliferous. The Eastern Flank There is much less outcrop of Ponnd Quartzite on this flank. This is partly due to Late Precambrian and early Cumbrian erosion and/or non-deposition. The upper member is totally absent in the vicinity of the Oxraparinna Diapir, us is the Parachilna Formation. Going northward, first the Parachilna Formation and then the upper member of the Pound Quartzite re-appear and thicken northward (Dalgarno, Johnson and Coats, 1964, 1:63,360 geological map, Blinman shect). Scction 18 at Wirrealpa Hill near Mt. Lyall was examined as it is one of the thickest sections of both members. Apart from some small circular shapes in the lower member which were probably due to mudflakes, no possible fossils were found. The mapped boundary between lower and upper members is not uwn- equivocal in this section, it was placed by Dalgarno and Johnson (1966) at the lower of two positions that seem equally possible, This placement results in sume médjum to rather fine red and white sandstones beige considered as low in the upper member in preference to high in the lower member. No fossils were taund. The Northern Flinders Ranges Only the southern tip of this broadly V-shaped revion was included in the arta studied, The only previous record of Precambrian fassils in this area (Sprige and Wilson, 1953) was of a single fossil jellyfish fram 3-3 km ENE of Mt. Urn, in the Pound Quartzite of the NW Hank of the Arrowie Basin, NE of Naring Basin (Fig. 2). About 33 km to the SW of this, on the SW side of Narina Basin, Patawarta Gap was investigated. The hill at the seuth side of the Ga {section 17) and the creeck-bed were examined. ‘he upper member is efiidsan as a serivs of four large questas of massive to Hat-bedded, white sandstone. Exposure is almost total, Surfaces are current-swept or ripple-marked and fine sediments are lackiny, ‘The lithology most closely resembles the upper member in the Wilpena Chalet section where sediments wlsa may have the winnowed appearance that results from medium to coarse sandstones, individually well- sorted, The underlying red, lower member consists of finer sandstones to siltstones and does not outcrop very well. It was nat completely traversed. A sharp-edged piece of float bearing faecal pellets was found in the creek; this és a greyish sand- DISTRIBUTION OF EBIACARA FAUNA 97 stone with maroon surfaces like the haematite-coated Hags from the lower fossil heds at Ediacara (Wade, 1968). In lithology it more ulosely resembled the kywer member than the upper but it was less battered than float which had travelled 1 km down the creek from the upper member. Lateral transport from between two questas ix suspected. This section js east and a little north of Green Well Creek, across an axial high with small exposures of diapirs. The most northerly fossiliferaus occurrence known is the section 1-4 km E of Mt. Scott (Fig, 3 (11)). Tt has been disenssed together with the correlation of other sections in the vicinity of Beltana Diapir (pp. 93, 94). Section 12 east of Puttapa Spring is also similar; it yielded doubttully tossiliferous float though no fossils were found in situ there. The syncline extending east from Patsy Springs Homestead past Angepena Hunnestead was investigated in two sections that proved to be ill-chosen (15, 16). The north limb, just south of Angepena Homestead, is overturned. It contains silty and clayey beds but these are somewhut defurmed; sandstones among them are massive, and there is a general lack of Haggy sediments. They do not resemble the Mt. Scott section. The south limb, near Mt, Wallace, is 2 much thicker section of fine to dominantly medium and coarse sandstones with some pebble hands, The preliminary Copley 1:250,000 shect shows it as a fault trough associated with the Mucatoona Diapir to the east and south. This diapir was apparently shedding sediment into the area during the tine of deposition of the Pound Quartzite, Caats {1964b) described evidence of instability at the Patsy Springs end of the syneline just prior to the deposition of the Wonoka Formation. The northernmost section studied (14) was that at Mundy Waters east of Leigh Creek, near Mt, Telford and just north of Booloorvo Diapir, Neither fossils nor fine-grained beds were found there. There was no clear-cut division into two or even three members. Sandstones tended ta reddish and roughly flaggy in the higher beds and ercyish and more massive in lower beds which were not con- tinuously exposed. OVERLYING SEDIMENTS Parackilna Formation In the Northern Flinders Ranges, both in the Angepena syneline and the Mundy Waters syncline, drab, olive-green siltstones with minor sandstones under- lic the sandy facies of the “worm burrow beds” with Diplocraterion and other burrows. In the Mundy Waters section, above the drab, olive-green siltstones aud interhedded barren, grey sandstones, the form Glaessner (1969) considered probably Rusophyeus Seilacher is 2 common fossil in sandstones crowded with less characteristic trails. The facies and fauna is closely similar to that from near the top of the Arumbera Formation (Glaessner, 1969) and may similarly be lowest Cambrian in age. Plagiogmus Roedel has also been recorded in this for- mation by Glaessner (1969), and Daily, Twidale and Alley (1969) who listed it fram sections overlying, the Pound Quartzite at Wilpena Pound. This net only reinforces the resemblance to the top of the Arumbera Formation where it also occurs (Ross River urea, east of Alice Springs but refines the Cambrian dating suggested by the probable Rusophycus by corrclation with the Swedish occurrance (pers. comm. Martinsson, in Glaessner, 1969) which was probably from the Lower Cambrian of Kalmarsund region. In the Angepena syncline the drub, olive-green sediments are thicker than at Mundy Waters and contain some beds of dark grey, impure sandstones that are crowded with “worm casts” of various sizes and a bifid trail resembling that figured by Glaessner (1969, 9B, C). Most of the trails, however, are simple, unbranched and horizontal, Above them are cleaner sandstones typical of the Diplocraterion facies which contain some beds of remarkably deep burrows; they BH M. WADE teach 0-6 m deep. Shales again predominate in the beds above the clean sand- stones. The olive-greon siltstones and sandstones were only observed in these two Northern Flinders synclines, where they appear conformable with the more wide- spread Diplocraterion facies of the Parachilna Formation apd to haye been included in this formation by Dalgarny (1964) who mentions its “mappable contact” with the Pound Quartzite in this area, TF we assume (Dalgarno, 1962; 1964) that the widespread occurrence of thick beds of the Diplocraterion sand- stone facies is everywhere the same age, then the Parachilna transgression must have started earlier in the Northen Flinders. The total thickness varies from tens of cm to nearly 50) m in the southern area but increases to 370 im in Lhe Arrowie cline, SE of Angepena syncline (Dalgarno, 1964; Horwitz, 1962). The Para- chihia Formation everywhere underlies the Wilkawillina Limestone (or the corre- lative Ajax Limestone, Daily, 1956; Dalgarno, 1964; Walter, 1967) and wherever investigated has above it a mid Lower Cambrian datum of relatively low in the Upper Aldan Stage, This datum was obtained by Walter (1967) from Archaco- eyatha from the middle pf the Wilkawillina Limestone. The base of the Wilka- willina Limestone is generally algal limestone and unzoned. From ity strativraphic posien we lave no cause to suspect a great age range within the Parachilna Formation which is probably all low Lower Cambrian. OCCURRENCE OF EDIACAKRA FAUNA The Ediavara farma is thus separated from the Low Cambrian by the time taken to deposit 600 m (or more) of Pound Quartzite, a major erosional interval, and the time occupied by a (?mikdly) diachronic transgression, The duration of these events is open fo many interpretations. Probably our best method of dating the Ediacara fauna is through the gradually improving correlation with related faunal elements that have been dated overseas, This (Glavssner, 1986 ) currently gives an age around 600-700 wy, It thus obliquely supports correlation of the Kimberley and Sturtlan to Marinoan gluciations. The known faunal content of the rocks is expanded hy every collecting wip. To date, every single fossil is of a form kuown from Ediacara Range. The present count of species is listed under the section numbers of the Jovulilies ju Table 1, TECTONIC SETTING OF SEDIMENTATION The distribution of the lower and upper members of the Pound Quartzite is not shown on the preliminary Copley 1:250,000 map but older mup legends show it is recugnizable over much of the area, The Cadnia 1:63,300 sheet (Grasso, Brock and Horwitz, 1960) mentions the reddish colour and shaley interbeds of the lower part. Sprige and Wilson (1953) were even more explicit on the Angepcua sheet (adjoining Cadnia on the north side); “Sandstone and quartzite slightly urkosic in part; principally light-coloured but thick reddish basal development particularly in the south westerly areas.” The southwesterly area is part of the wose of the Mt. Scott Range syncline and the description indicates that the twe members are no Jess distinct here than in sections 11 and 12 near Mt, Scott and Puttapa Spring; they may well be more distinutive, being further from the Beltani Diapir complex and ihe associated orthoquartzitie heds in the lower ember (pp, 4), E Lae (1968b) does not discuss the Pound Quartzite individually but figures it (fig. 27) as a coarser stipple overlying a finer one, both increasing in thickness to represent about 1,200 m of sediment each in the extreme north of Northern Flinders Ranges. This preat increase in thickness implies differential fectuniy ynoyernents oyer a long time and indicates that the shallowing and the supply of coarser sediments that resulted in the upper member of the Pound DISTRIBUTION OF EDIACARA FAUNA 99 TABLE 1 The known components of the Ediacara fauna and the areas frem which they have been collected, Section numbers refer to Fig, 2. The entire fauna from Ediacara Range has been listed under section 10 for convenience. *"Kimberia® Glavssner and Wade, 1966, not Kimberia Cotton and Woods, 1935. Beetion No. 1)2)3) 6) 6) 7) 8] 8} 10) 11 | 12)13)17 a ae | mf A | | bady fossils: coarse, spicular impressions indeterminat: meduasoids Ediacaria fanderst Sprige of x | ef} x Beltanella gilest Sprigg Medusinites asteroides (Sprigg) Cyclomedusa, davidi Aprigg x x C. radiata Sprigg C. plone Glaesener & Wade er? ap. x Muwsoniles spriggi G. & W. Conomedusites lobatus G. & W. x *Kimberia quadraia G. & W. Rugovorites enigmaticus G. & W. x medusvid, n. sp, | x |x | at * 4 4 “wd modus, n, sp. Lerenzinites rarus GO, & W. Ovatoscuium concentricum G. & W. Chondrophore, n. gen., . 6p. Range longa G. & W. Rt. grandis G. & W. Pleridinium simplex (Givich) Arboren arborea (Gluessner) Dickinsonia. costaia Sprize D, elongata G. & W. D. tenuis G. & W. | Spriqgine flounderst Claessner Spriggina? cuain Cy, de W. x Praecambridium signlum G. & W. Parvancorina minchami Glaessner x Vribachidium heraldiewm Glaessner x x trace fossils: Pseudlorkizostomiles howching Sprigg x x * Form A (Glacssner, 1969) x Form B (Glessner, 1969) x/x|x]|x|)x]x/) x Form C (Glacssner, 1969) Form D (Glinessner, 1969) Form E (Glaessner, 1969) x Form ¥ (Glsessner, 1969) x 3-poimt imprints (undescribed) x x + ve trail (undeseribed) x| x of x a4 tad HAR AAR KR KAR HR RAM OM HRA ARR RK RR RO ef AAAM AAR OK ~~ Quartzite, are more probably the result of increased tectonism than some custatic pene, Glacial eustatic processes are most unlikely for the geologic instant was ong after the deposition of the partly glacial Lower Marinoan Elatina Formation and the Middle Marinoan expansion of sedimentation which Thompson (1969b) suggested could be explained this way. The six sections studied in the Northern Flinders Ranges (fig, 2 (11, 12, 14-17) ) show more variability during Pound Quartzite sedimentation than is recorded in the Southern and Central Flinders ranges but 11 and 12 were asso- ciated in documented movements of Beltana Diapir, 15 and 16 with partly documented moyements of Mucatoona Diapir, and 14 is very close to Boolooroo Diapir thongh only post-Lower Cambrian movements are yet documented for 100 M, WADE that, Only Patawarta Gap (17) scems to have been in a stable area, and fo differ From the southern and western sections only in its greater thickness.. The conclusion that the northern area was more actively subsiding than the southern Is inescapeable but the roles played by diapirism may appear more strongly differentiated than they actually were. Deep erosion in the axial region of the Central and Southern Flinders Ranges has removed the Cumbrian aud Upper Murinoan from the neighbourhood of a number of diapirs, and thus reveals mare evidence of early movements of the diapirs there, and reeords less of their later movements, The less deeply eroded areas show more evidence of the younger movements while the older rocks are covered. Shortly after the onset of coarser (upper member) scdimentution, an elongate deposit of fine sands with minor silts to clays formed (Fig, 3) west of whats now an axial high extending south from latitude 30°45’ The only definitive edge to the fine sediments is found at Wilpena Pound where massive sandstones like those at Patawarta Gap are in line with a low tn the axial structure as at present expressed —a gap between two diapirs that had commenced movernent by the Sturtian (Dalgarno and Johnson, 1966). The mare northerly of these continued its move- ments intermittently into the Cambrian (Oraparinne Diupir, Dalgarno, 1964; Walter, 1967). No post-Sturlian rocks are associated with the more southerly. All of the larger diapirs on this axis have histories of movement dating back to the Sturtian, except Beltana Diapir which is surrounded by Middle and Upper Marinoan racks lo bath of which it contributed coarser sediments. The observa- tions of Coats (19641) and Dalgamo (1964) on the extent of the movements receive additional documentation from the maps of Dalgarno and Johnson (1966) and Leeson and Nixon (1966) and from Leeson (1970), After the short, and varionsly interrupted, period of deposition of fine sediments the area returned ta the deposition of coarse- to medium-grained, white sands, strongly cross-hedelesl and ripple-marked, and with intermittent slump rolls—the cross-stratified to Hat- stratified facies of Goldring and Curnow ( 1967), Alternative explanations for this distribution of fine sediments must take decreasing ettect of water movement into account. This could have been caused either by the deepening of the water column over the region of the present Mt. Seolt syricline. west Hank area and Chace and Druid syncline, or by the formation of barricrs reducing wave action. Though m this region only the Beltana Diapic shed boulders into the Pound Quartzite—and Ubul earlier than the widespread change of sedimentary pattern in the south—it hardly seems possible that a general shallowing could affect the basin without re-activating al least some of the pre-existent diapirs, Frome Diapir, east of Mt, Lyall, was eroded at this time (Coats, 19642). he formation of sheltered areas of sea Aoar on the landward (wesF) side of shoals in the general position of re-activated, known diapirs seems the most likely explanation of the short-lived deposition of fine sediments in this shallow sea. Erosion in the axial region has proceeded to a depth that has removed most evidence but statistical work may show maxima in the direction af movement of slump ralls, for instance, which would show the alirection of the high or highs that shed them. At Parachilna Gorge they even occurred inter- inittently during the deposition of the fine sediments. OUTLYING OCCURRENCES Two single specimens, cach of a pennatulid on a loose rock slah, have been found beyond the confines of the Adelaide Geosynclinc (Text-fig. Ll; x, ¥)- Arborea arborea { Glaesmaet | was found al Jocality x, 27°45", 190°30’, in the uppermost Precambrian Punkerri Sandstone which is correlated with the Pound DISTRIBUTION OF EDIACAKA PAUNA 1D] Quurtzite but uot well exposed (pers. conun., R. B. Major). Rangea cf longa Glaessner and Wade was found at lovalily y, east of Deep Well Homestead, 80 km SSE of Alice Springs), in the lower part of the Arumbera Sandstone (Claess- ner, 1969). Tho specimen is identical with Ediacara specimens lacking preserved seganthaty branches (anthosteles}; these have similarly been called Rangea cf. onga. “The Arumbera Sandstone is Lower Cambrian at its top (Glaessner, ee) and is conformable with the Precambrian Pertatataka Formation (Wells, ef al. 1967; Forman and Milligan, 1967, maps only, pls. 10-13), These authors provision- ully considered the entire formation Cambrian though Wells e¢ al. noted that the base could be Precambrian. The known fauna consists mostly of the trails and burrows described by Glaessner (1969) mainly from a bed about three-quarters the distance from bottom to top of the formation, and higher, (The existence of two published variants of the thickness in the Laura Creek region, 23 km WSW of Alice Springs, 600 m and 430 m, leads me to prefer to render the relative sitions as ratios). The commonest trace fossil, by Held chservation, is a small Hlarieter, unnamed burrow filling (Glaessner, L969, fig, G£) which also may occur in the finer sediments right down to (but not in) the lowest ridge-forming sand- store a little fess thin one ‘uurter the distance from base fo top. About two-thirds of the distance from the base to top the well-preserved but undescribed medsoid colleeted by G. K. Williams was obtained (Claessner, 1969; G. K. Williarns, pers. com, ); one specimen of an epichnial groove inseparable from Glaessner’s l'onn B in the Ediacara fauna was collected half way through the formation, and a few Hallidaya bruert Wade from one quarter the distance from base to top (Wade, 1969). The Ranges from Deep Well was said to be from near the base of the Arnimbera. sandstone. The known fauna may be summarized as: one form known from the Ediacara Fauna fron near the base, 2 medusoids nat known from the Ediacara fanna ond 2 trace Fossils with overlapping ranges, one previously known from the Ediacara fauna and one from the Cambrian, from the ventral part of the formation, and several Cambrinn trace fossils from the upper quurter. Thus whether we accept the evidence of bridging of the Cambrian to Precambrian boundary oF not, we have clanents of a fauna which must represent at least the upper part of the time unrecorded in the Adelaide Geosyncline, duc to the unconformity between the Pound Quartzite and Parachilna Formation. Webby (1970) has comprehensively described the lately-discovered trace fossil faunas of the Fowlers Gap Beds and the Lintiss Vale Beds in north-west New South Wales (Fig. Iz), It is unfortunate that not many of his forms are very distinctive but most satisfactory to have a deseription of the complete fauna- Webby noted that about 3 times as many kinds of activity were present in the upper fauna (from the Lintiss Vale Beds) as in the lower (Fowlers Gap Beds) tauna, He pointed out that the same conclusion could be derived from his material as from Jiteratsre, that the trace fossil faunas become richer as the Cambrian is approached, Glaessner (1969) came to the same conclusion fram comparison of literature, the Precambrian Kdiacara fauna trace fossils and the definitely low Lower Cambrian Arumbera Sandstone fauna. Webby based his decision that he was dealing with a Precambrian fauna on the absence of Arthropod markings and most complex burrows, though he noted some typically Cambrian forms, a new Phycedes? and bilobed and trilohed trails in his upper fauna. His Fig, 11 could be a fragment of Plagiogmus which is sometimes pre- served as a burrow filling but even disregarding this possibility there are close resemblances between the Parachilna-Arumbera fauna and the Lintiss Vale fauna. Phycodes? antecedens Webby is admittedly close to Phycodes pedum Scilacher 102 M. WADE which oceurs in the Arumbera and possibly is also present iu the Parachilna Formation at Mundy Waters. The bilobed trail (Webby, 1970, Fig. 124,B) appears identical with the Parachilna Formation form figured by Cliuessner (L969, Fig. 9B. C), Planolites ballandus Webby (1970, Fig, 144, C) can be duplicated from the Arumbera Sandstone, Gordia sp. of Glacssner (1969, Fig, 9F) is an external mould identical in shape and size to Cochlichnus serpens Webby. Small, curved trails differing from Torrowangea rosei Webby by the pellets being less clusely packed and the curves smoother and more open, occur below the richly fassiliferous sandstone three-quarters the distance from bottom to top of the Arumbera Sandstone. The aspect of the Lintisy Vale trace fossil fauna is more like the low Lower Cambrian fauna than the Ediacaran, If further collecting fails to produce mure of the Cambrian clement in the fauna, its age will have to be considered inter mediate between the low, Lower Cambrian and the Ediacara fauna. The Ediacara faunit, must be re-sought below the Lintiss Vale Beds, The Fowlers Gup fauna would not appear out of place in the Ediacuran but is too poor in date. CONCLUSIONS The Jong-awaited evidence on the stratigraphic placement of the Ediacura fauna las been provided by a band of fossiliferous rocks near the base of the upper member of the Pound Quartzile. This so closcly parallels the boundary heiween the lower and upper members as to entitle us to regard this boundary as a time plane through the western side ef the Flinders Ranges. It also highlights the tremendous amount of erosion that took place on the ‘Tovally Inconspicuuus unconformity between Pound Quartzite and ParachiIna Formation. The thinning af the lower member at Ediacara Range has to be regarded as a depositional thinning since both the typical “lower member” beds and the “red and white sandstones” above tiem are thinned in the same proportions relative to the Mt. Seott and Red Range sections. The upper member could owe its thinning here only to crosion (Fig. 3 (10) ) as the beds below the fossils are of average thick- ness, but erosion has removed the evidence. Evidence of repeated movement on the diapirie cores from Sturtian to post lower Cambrian continues tu mount. It appears clearer Unat the major strati- graphic highs scen in the zone of diapirism today have been highs repeated|y since the Sturtian and were not re-elevated by hare in the Tower Palavozoic folding of the geosyncline. The discovery that a low Lower Cambrian fauna in the wpper quarter of the Arutnlera Sandstone is correlatable to the Parachilna Formation (Gluessner, 1969) reveals the fact that the differing fauna in the middle of the Arumbers Sandstone represents a zone above the Ediacara fauna. Whether this should be assigned to the Cambrisn or the Precambrian will await inter-regional correlation. The discovery of a fauna of about this age near the top of a continuals sequence in northwest New South Wales (Webby, 1970) gives a second possibility at establishing the Precambrian-Cambrian boundary in a continuously zoned sue- cession, as has been done with later era houndaries. This area may provide a suitable subsiduary section for the top of the Upper Marinoan. ACKNOWLEDGMENTS Part of the field work was supported by an Australian Research Grant to Frofessor M. F, Glaessner, aud part by the University of Adelaide. 1 have had the benefit of numerous discussions with Professor Glaessner during the course ol this work, and his criticism. A number of people have assisted with the field work at vurious times; the assistance of Mr. J. C. Cebling has been outstanding. DISTRIBUTION OF EDIACARA FAUNA 103 REFERENCES Bixxs, P, J., Forses, B. G., and Mmans, R. C., 1968. 1:250,000 geologic map, Orratno, Geol. Sury, South Aust. Casrana, B,, 1958, The Mt. 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Early Cambrian “jellyfishes” of Ediacara, South Australia, and Mount abe, “Sambatey District, Western Australia. Trans, R. Soc. S. Aust., 73 (1), 72-99, pl. 9-21. Senicc, R. C., and Wirson, B., 1953. 1” to 1 mile geologic map, Angepena. Geol. Sury. South Aust. TrespaLe-Smitn, E. N., 1959. Bibliography of South Australian Geology. Geol. Surv. South Aust., pp, 1-285. Tuomson, B. P., 1966. The lower boundary of the Adelaide System and older basement relationships in South Australia. J, Geol. Soc. Aust., 18 (1), 203-228. Tuomson, B. P., 1969a. The Barrier Ranges, in PacknamM, G. H., ed., The geology of New South Wales. J. Geol. Soc. Aust., 16 (1), 55, 57-64. Tuomson, B. P., 1969b. Precambrian crystalline basement. Precambrian basement cover. The Adelaide System. in Panxry, L. W., ed., Handbook of South Australian Geology, Geol. Surv. South Aust., 21-83. Tuomson, B. P., Coats, R. P., Mmams, R. C., Fores, B. G,, DALGARNO, C, R., and Jounson, J. E., 1964. Precambrian rock groups in the Adelaide Geosyncline: a new subdivision. Quart. geol. Notes, Geol. Surv, South Aust., 9, 1-19. Wane, M., 1968. Preservation of soft-bodied animals in Precambrian sandstones at Ediacara, South Australia. Lethaia, 1 (38), 238-267. Wave, M., 1969. Medusae from uppermost Precambrian or Cambrian sandstones, central Australia. Palaeontology, 12 (3), 351-365, pl. 68, 69. Watter, M. R., 1967. Archaeocyatha and the biostratigraphy of the Lower Cambrian Hawker Group, South Australia. J. Geol. Soc. Aust., 14 (1), 139-152, pl. 7, 8. Wespy, B. D., 1970. Late Precambrian trace fossils from New South Wales, Lethaia, 3 (1), 79-109, Weuts, A. T., Ranrorp, L, C., Srewarr, A. J., Coox, P, be and Suaw, R. D., 1967. Geology of the north-eastern part of the Amadeus Basin, Northern Territory, Bur, Min. Res., Rep. 113, 1-93, THE SUBLITTORAL ECOLOGY OF WEST ISLAND, SOUTH AUSTRALIA 1. ENVIRONMENTAL FEATURES AND THE ALGAL ECOLOGY BY S. A. SHEPHERD? AND H. B. S. WOMERSLEY* Summary An account is given of the sublittoral marine algal ecology of West Island, a small island lying at the western end of Encounter Bay, South Australia. Environmental factors and the algal zonation and associations to a depth of 28 m are described. On rough shores three zones are evident but on the sheltered lee shore the uppermost zone is very restricted and the lowermost zone does not occur due to the limited water depth. The upper sublittoral zone is colonised by a short red-algal turf comprising species tolerant of turbulent water and strong light, with a sublittoral fringe of Cystophora intermedia present only in the roughest areas. The mid sublittoral zone is dominated by larger brown algae and the lower sublittoral by a mixed association of red algae growing under conditions of low light and slight surge. Water movement and light are probably the two most important ecological factors in the sublittoral. Horizontally species’ range is largely determined by water movement but vertically light is the more important; however, it is evident that the mid sublittoral zone of large brown algae occurs at greater depth under rougher conditions, and several other species follow this pattern, The depth range of most species can vary considerably depending on the interplay of light, water movement, aspect and probably other less conspicuous factors. Estimates are given of the standing crop of algae within various associations. THE SUBLITTORAL, ECOLOGY OF WEST ISLAND, SOUTH AUSTRALIA 1, ENVIRONMENTAL FEATURES AND THE ALGAL ECOLOGY by S. A. Saepuenp} anp H. B. S. Womerster* SUMMARY An account is given of the sublittoral marine algal ecology of West Island, a small island lying at the western end of Enepunter Bay, South Australia. Environmental faetars and the alyal zon#tion and associations to a depth of 28’ m are described, On rough shores three zones are evident but on the sheltered lee shore the uppermost zone is very restricted and the lowerinost «one does not occur due to the limited water depth, The upper sublittoral zone is colonised by .a short red-algal turf comprising species tolerant of turbulent water and. strong light, with a sublittoral fringe nf Cystophora intermedia present only in the roughest areas. The mid sublittoral zune is dominated by larger brown algae and the lower sublittoral by a mixed association of red algae growing under conditions of low light and slight surge. Water movement and light are probably the two most important ocological factors in the sublittoral, Horizontally species’ range is largely determined hy water movement but vertically light is the more important; however, it is evident that the mid subliitoral zone of large brown algae occurs at greater depth under rougher conditions, and several other species follow this pattern. The depth range of most species can vary considerably depending on the mter- play a light, water movement. aspect and probably other less conspicuous actors. Estimates are given of the standing crop of algae within various associations. INTRODUCTION Although the intertidal ecology of the southern Australian coast is fairly well knuwn (Bennett & Pope 1953, 1960; Womersley 1947, 1948, 1956a; Womersley & Edmonds 1952, 1958), the only study within this region of the subtidal algal ecology and distribution, based on collections made in situ, is that in the almost enclosed Port Phillip Bay, Victoria (Womersley 1966). This contrasts with the situation in the northern hemisphere where pioneer studies in subtidal ecology were mude by Cislen (1930) in a Swedish fjord, using helmet diving equipment, and by Feldmann (1937) in the Mediterranean. With the advent of SCUBA equipment, sublittoral surveys have been carried out on many coasts, including those of Europe (Forster 1961, Jorde 1966, Kain 1960, Kitching 1941, Séderstrém 1965). the Mediterranean (Crossett & Larkum 1966, Pérés 1967, Vacclet 1967), Asia (Petrov 1967, Vozzhinskaya 1965), North America (Edelstein et al, 1969, McLean 1962, Neushul 1965), New Zealand (Bergquist 1960a,b) and the Antarctic (Zancveld 1966). Thus knowledge of subtidal marine organisms and their ecology in Australia is largely limited to the uppermost sublittoral as ohserved during very low tides or by shallow diving and visual observation from the surface. The sublittoral on rough coasts, which comprise most of the southern Australian coastline, is virtually unknown, though the rich algal flora has been fairly well documented from drift collections. f Department of Fisheries and Fauna Conservation. Adelaide. ° Department of Botany, University of Adelaide. Trans, R, Soc. S, Aust, (1970), Vol. 94. L0G SA. SHEPHERD 4xp H. B.S, WOMERSLEY The ecology of subtidal communities of marine algae and sea-grasses is of basic importance in many marine studies and, together witli floristic studies of such communities, is a Valuable indicator of the biogeogruphic relationships of a zegion. Subtidal, rather than intertidal, organisms are probably better for this purpose since they are not subject to the extremes of temperature and other conditions in the intertidal region, West Island was chosen for study because of its easy accessibility yet suitable position subject to rough conditions with no protection from the south-west, Riotic communities on such off-shore islands generally have a richer flora and fauna than communities in more sheltered waters, This is probably becanse physical conditions in the water aré more favourable and less variable. While waler muvement is usually greater around off-shore islands, Nuctnations in temperature, sulinity, oxygenulion and turbidity are smaller and sand scour ts almost absent. West Island is of a suitable size for a study of the effect of wave action which varies greatly fram windward to lee shores around the island: also the presence of steep under-water slopes permits a study of communities in relation to depth, The aspect of subtidal rock surfaces is of considerable importance. Upward facing surfaces are dominated by algae but, as a ruck fave approaches the vertical, faunal elements increase and algal density decreases, In caves, crevices and nnder overhangs, algae are mostly absent und animals predominate, as has been deserihed by Crossett & Larkum (1966), Pérés & Picard (1949) and Vacelet (1967). This is due almost entirely to low light intensity and re-cmphasizes that alvae usually dominate the photic zone while animils dominate places where light is inadequate for plant growth, While some animal commmunitics do occur within the photie zone, Veision of synecological studies into faunistic and floristic aspects is convenient. In the following account, horizontal and sloping to vertical surfaves are considered, but not othicr surfaces subject to reduced light where the fauna predominates. The animals which are prominent among the algal com- munities are mentioned briedly. This account of the sulitidal algal vegetation of West Island is of more than loval interest, since many of the communities and the basic zonation are found elsewhere in rough areas of the central coast of South Australia. The intertidal zone is excluded from this account since the discussion of Womersley and ieee (1958) for rough to sheltered, steeply sloping coasts applies ta West Istand. METHODS The survey on which this study is baseql was carried out hy the first author with SCUBA equipment between December 1965 and May 1968, with occasional observations since then. The island was visited on fifty occasions at fortnightly or monthly intervals during the study period and more than seventy hours were spent underwater, Notes were taken on sand-blasted perspex and algal (and faunal) collections were made at numerous localities about the island. Determi- nations of algae were made by the second author. Specimens of all species are lodged in the herbarium of the Botany Department, University of Adelaide ADU). 5 All depths given in this paper are in metres and are based on the low water neap tide level for Victor Harbor, This “datum level” is used for Figures 7-14 and the eulittoral—sublittoral boundary varies from this as indicated on Figure 6, Initially, a general survey was made of the arca and the algae collectect for identification. Then followed a more careful survey and the relutive abundance ENVIRONMENTAL FEATURES AND ALGAL ECOLOGY 107 and range of individual species were noted. Finally, quantitative estimates were made of the density of algac at several points about the island. The continuous south-west swell made collecting difficult and hazardous on the southern and western shores, and the upper sublittoral zone at these localities was only accessible after days of protracted calm weather. On only two avceasions during the period was the swell low enough to permit diving at upper levels at Lands End. AREA SURVEYED West Island (Pl, 1) is a granile knoll of about 13 hectares (33 acres) rising to a height of 40 m, about 800 m offshore at the north west end of Encounter Bay (Lat. 35°37", Long, 138°35’). The island is figured and its geology discussed by Howchin (1910, p. 7, pl. XL). Some prominent features on the island and locality names used during the survey are shown in Figure 1 and Plate 1. Along the windward southern face, steep cliffs fall abruptly to the intertidal and continue to a sandy sea floor at a depth of about 29 m, Underwater the granitic blocks have broad sloping faces and form between them crevices, caverns and overhangs. a Penguin-Rock “AO Restless is - WEST IS. ha A-Extent of a subl|traral rock “REGION Aw ¢ . ‘Seal Rack Lands End-~ a Oedipus-Pto y tggm. 4 2 Fig, 1 Map of West Island. While the underwater topography provides many different microhabitats with a great diversity of plants and animals, there are also extensive areas of uniform algal growth, Along the eastern and western shores the sea floor gradually rises (see Figure 4), The continual breakers on much of the western shore prevented a detailed examination of the sea floor, The northern shore of the island between Restless Point and Penguin Rock is Jow and slopes to. the sea bed at about 5 m, In many places rounded granite boulders up to 50 cm across lic down the slope and are scattered on the bottom, and two shallow rocky sills run shorewards at a depth of about 3 m. To the lee of the island, extensive beds of marine angiosperms stabilize the sandy sea-bed. 108 8, A. SHEPHERD anv H. B.S. WOMERSLEY ENVIRONMENTAL FACTORS (a) Temperature West Island is reported to lie between the summer and winter surface sea isotherms of 19° and 13°C (Womersley and Edmonds 1958). Temperature readings were taken from the surface to the bottom at 5 m intervals in the open sea outside the island, at monthly intervals for three years, Figure 2 shows that the annual range in surface temperature is about 8°C. Surface temperature readings from the winter of 1967 until the winter of 1968 were relatively high, averaging about 2°C above those recorded in the previous two years, while summer temperatures in 1969 and 1970 were lower, the highest readings being 195°C, Temperatures did not vary greatly from the surface to the bottom. A thermo- cline was sometimes recorded between 15 and 20 m during calm periods in summer when the surface water was from 1-3°C warmer than deeper water. This was no doubt due to the heating by radiation of the upper water column, together with lack of mixing. Conversely, in late autumn, the surface watcrs cooled more quickly and were sometimes up to 1°C cooler than the water between 20 and 28m, Between July and October a bottom layer of turbid water up to 3 m thick was sometimes found to vary up to 1°C above or below that of the superjacent water. 24 Fig. 2 Sea surface temperatures in 1965-67 taken 20-30 m aff the south-east coast of West Island. The broken lines indicate the extreme range, and the solid linc shows the averages for the period. A 5S 0 N DBD +} F M A M JS J months (b) Waves, Stwell and Surge Wave cnergy reaching the island is of three main types (i) Prevailing Swell. This is generated in the Southern Ocean well south of the continent and prevails throughout the year; the direction of approach is south-west, ENVIRONMENTAL FEATURES AND ALGAL ECOLOGY 109 (ii) Local Seas. These are caused by local winds, When the winds are offshore (i.e. from the east through north to west) waves of short wave length (period < 3 seconds) are generated. These produce no surge and are of little significance in the sublittoral zonc. Qu-shore winds produce wayes which combine with the swell and reinforce it, (iii) Local Swell, In early summer (November and December), the pre- vailing winds are from the south to south-cast. During these months a short swell is generated from that direction with a period of 5 to 6 seconds. This may be superimposed on the prevailing swell causing the combined swells to periodically reinforce each other, Local swell is unusual at other times of the year. FR law swetl WE Modsrare swell TSHeary swell Fig. 8 Average monthly distribution of days of low, moderate and heavy swell for the years 1965-1967 at Neptune Is. Prevailing swell conditions from 1965 to 1967 as recorded at Neptune Island (at the southern end of Spencer Gulf) are shown in Figure 3 and indicate the situation at West Island. Although oceanic swell is on the average more severe during winter, periods af very low swell may occur ut any time of the year. The observed swell characteristics are shown in Table 1, Wave lengths were determined from aerial photographs, Vig. 4 Suecessive wave crests {broken lines) about West Island. Figures (within the island cutline) are wave heights expressed as percentage of maximum height ut Lands End, Depths are in metres. The position of West Island is shown on the inset map of the South Australian coast. directicn of ~f_ weit — In this paper the term “surge” is used to refer to the rapid sub-surface horizontal water movements with abrupt reversals of flow caused by the swell as it passes over shallowing water, In deep water, as a wave passes, any particle of water describes a circle the radius of which decreases with depth, However, on approaching an island barrier the water will surge to and fro more or less hori- zontally, This effect is most severe near the surface and decreases with depth. 110 8. A. SHEPHERD awn H. B, S. WOMERSLEY TABLE 1 Observed prevailing swell corlitions at West Island Swell Wave Height Period | Wave Length Range | (metres) (seconds) (metres) Low (u-5—) 1-2 Moderate t 2—3 1g — 12 110 — 120 Heavy | over 3 I } The degree of water movement is of great significance in its effect upon algal growth but it has not yet been satisfactorily measured, The methods of Jones and Demetropoulos (1965, 1968) and Muus (1968) are not readily applicable to under-water studies. Despite the lack of accuvate measurements, biological indicators and some local knowledge will generally enable « reasonably good assessment of surge conditions to be made. There is no doubt that occasional very rough seas do more damage to algae by mechanical action of surge than do average conditions. The prevailing swell strikes the island on the southern and western shores, reaching maximal force at Lands End. The distribution of wave height about the island is controlled largely by diffractive effects although on the northern shore some wave refraction occurs inshore (see Figure 4). The two submerged reefs on the northern shore and the dense sea-grass meadows in shallow water cumu- latively attennate the swell so that in Abalone Cove it is reduced to about 20% of its original height. At Abalone Cove the waves passing around each side of the island intersect, resulting in a continual though slight surge. Figure 4 shows successive wave crests and estimated wave heights at various localities expressed as a percentage of wave height at the roughest location. (c) Visibility and Submarine Illumination The island is washed by oceanic water which is virtually free from suspended silt discharged from mainland rivers, Occasionally (usually September to November) after strong southerlics, tongues of turbid water may extend west- ward from the River Murray mouth (about 24 km to the cast) to the vicinity of West Island, but these are rapidly dispersed by a change itv weather. TABLE 2 Underwater Visthility off West Island Conditions Visibility at depth of 0 — 20m 20 — 20m 1. October to Vebruary Low Swell 7 — 12m 2 — bmi Moderate Swell About 5m 1 — 2m 2. March to September Low Swell 10 — 1lom 3 — 10m Moderate Swell 5 — Tm 1 — 2m ENVIRONMENTAL FEATURES AND ALGAL ECOLOGY lit _ Visibility is fairly uniform down to about 20 m but below this drops sharply. The degree of turbidity is related to swell conditions, Bottom sediments are stired up through agitation of the sea-bed by surge and water turbidity is greatest near the bottom, depending on the duration and severity of the swell. The approximate range of visibility during the year is shown in Table 2. After a prolonged calm, visibility near the bottom may rise to the maximum shown in the Table but usually lies between 1 aud 4 m, Water transparency was found to be gencrally lower during summer than at other times. An increase in plankton may be responsible for the reduction in transparency, but this has not been investigated. Light readings using a photometer in a watertight case were taken from the surface to the bottom at 5 m intervals outside the island, monthly for 12 months. The readings were all taken with the sun at zenith and with a clear sky. Light intensitics vary according to water turbidity and the range in values down to 26m (expressed as a percentage of subsurface illumination) is shown in Figure 5. The illumination for clearest and average oceanic water and for average coast) water (after Sverdrup et al. 1942, p. 776) is also given in Figure 5 for comparison. ‘The transmission values for the waters off West Island lie between the valuus for average ocean water and average coastal water. In addition the horizontal illumination wis measured ut various depths to determine the mtensity of light falling on 2 vertical rack face (Poole and Atkins 1929, Strickland 1958, p. 472). The ratio of horizontal to downward illumination ut various depths is shown in Table 3. The highest perecntages were recorded from waters of average transparency and the lowest from turbid water; the percentages for yery clear water were slightly below the averages recorded, On rare occasions, however, neur the bottom, light reflected upward from the sand intreased the level of light by as much as 50‘. TABLE 3 Ratios of horizantal.ta downward ilhemination at various depths qeprassed as «2 percentage of downward vllumination Depth (metres) Subsurtace 6 13 19 26 Extreme Range (%) 20 — 25 25. — 18 10 — Att i — 40 1) —- 25 Avecage 2, 24 3 33 al ia (d) Seour and Sedimentation Scour by sand does not occur duc to the absence of surge at the sublittoral base of the island where rock meets the sand. The waters of these rough shores are free from sediment, so that sill is absent from rock surfaces to at least 25 m. Below this depth sediments stirred up by swell may sometimes setile on rock, On the lee of the island also, sediments of fine sand may accumulate on a horizontal rack surface which is in an exceptionally protected site. (ev) Other Factors No measurements were made of salinity, phosphate, nitrate, alkalinity or of the level of dissolved oxygen. The figures given by Womersley (1947, p. 25) for the south coast of Kangaroo Island are probably applicable to West Island. Kirkwood (1987) gives figures for organic phosphorus, inorganic phosphate arul nitrate in South Australian waters. These factors are so stable that they are unlikely to contribute to community differences in the region studied, 112 5. A. SHEPHERD ann H, B.S. WOMERSLEY TERMINOLOGY With the probable development of further underwater studies, there is a need for uniformity in terminology. The proposals made here are applicable to southern Australian coasts and aecord with observations made elsewhere by many ather authors. (1) Horizontal Distribution On rough coasts of southern Australia surge is a principal factor affecting algal distribution (Womersley 1947, p. 236) and hence a classification of the benthic-plant environment should be related to this factor. The coastal sub- forme fons of Womersley (1947) might be adapted for sublittoral conditions as ollows: Rough coast sub-formation (i.e, subject to prevailing swell). (i) Strong to extreme surge, (ii) Moderate surge. Womersley’s “sheltered rocky coast sub-formation” then refers to a coasl subject to a slight surge caused by swell or by wind-driven waves of short wave length. Berinett and Pope (1960, p. 221) use similar degrees of roughness and take the wave strength at Cape Bridgewater as a standard maximum. Wave action at Lands End, although not as severe as that at Cape Bridgewater, is of the same order, (2) Vertical Zonation A sharp distinction between zones is less apparent in the sublittoral than in the intertidal zone and plant zonation is seen rather as a gradation from one association to another. Nevertheless Jorde and Klayestad (1963) and Nenshul (1965) describe three vertical algal zones and Bergquist (1960a,b), McLean (1962), Jorde (1966), Petrov (1967) and others describe an upper and lower zone in the sublittoral. In southern Australia usually three. sometimes two, zones according to locality and roughness, can be recognised. Figure 6 illustrates the terminology used. Most writers recognise similar vertical subdivisions (sec Hedg- peth (1957, p. 19) and Petroy (1967) where the terminology used by various ROUGH SHELTERED # _ EWLITTORAL \ UPPER SUBLITTORAL —_— — a ama tae 6 MID SUBLITTORAL =e see —_— | womans 2- = in Mam am= 2— wl S| TOWER SUBLITTQRAL Fig. 5 Range in transmission values for waters off West Island during low swell are shown in (left) the shaded area, Other values.are; 1, Clearest ocean water (after Sverdrup), 2. Average ocean water (after Syerdrup). 8, Average of values recorded during low swell. 4. Most turbid water recorded durimg moderate swell. 5. Average coastal water (after Sverdrup). Fig. 6 Zones of the sublittoral showing the depth variation from rough to sheltered water, right) ENVIRONMENTAL FEATURES AND ALGAL ECOLOGY 113 writers is summarised), the differences between them being in naming of the zones only. Pérés (1967) discusses a similar scheme based on intensity of water movement at different depths. The term “upper sublittoral” reters to the upper zone which on most coasts is characterised by a short algal turf but on rough coasts in the cooler waters of Victoria and Tasmania is dominated by the “bull-kelp”, Durvillea potalorum, On rough coasts the zone may descend to 5m; in these conditions the highest part, emergent between waves at low tide, is characterised by distinctive species (e.g. Cystophora intermedia) and is referred to as the sublittoral fringe (Womersley and Edmonds 1952; Bennett and Pope 1960, p. 198). The mid and lower levels of the sublittoral are characterised by communities of brown algac and red algae respectively. These zones are biologically characterised entities and their boundaries vary according to the physical conditions. Figure 6 shows the shift in boundaries from ruugh to sheltered conditions, The most striking effect is that under shellered conditions the upper sublittoral zone of algal turf is very narrow and the mid sublittoral zone of brown algae extends to low tide level. (3) Association and community The term “association” is used as in intertidal ecology (e.g. Womersley 1948) to refer to distinctive groupings of one or more species occurring repeatedly in a Particular environment. The term “community” is less precise and refers generally tu moderately distinct aggregations of plants. Further characterisation of evo- logical groupings in the sub-littoral must depend on future studies and at this stage more precise definitions are not attempted. ZONATION AND DISTRIBUTION AROUND ‘THE ISLAND The general features of the algal vegetation change markedly around the isfand in passing from reugh to more sheltered cuasls. The shores have therefore been divided into four regions, each of which his algal communities with characteristic features. The changes in the vegetation from one region fo another are seldom sharp yet occur over a relatively short distance, indicating a distinet gradient in one or more environmental factors. (1) Region A. The rough-water southern and western coasts bebween Toad IIead and Restless Point. (II) Regions B and C, The moderately rough-water disjunct sections on the eastern and northern shores, (IL) Region D, The semi-sheltered seelion in Abalone Cave. (1). REGION A (ROUGLU WATER) Wave action is generally strang and reaches its greatest force on the south- western side. Here the splash zone extends upwards to more than 20 m above sea level and the littorinid snail Melaraphe unifasciata (Gray) is common at this height, In conditions of such extreme roughness, both the enlittoral zone and the upper boundary of the sublittoral zone are elevated relative ta mean sea level (cf. S6derstrém 1965), and Cystophora intermedia which has heen used as an indicator of the upper boundary of the sublittoral (Womersley and Edmonds 1958) forms a narrow belt (sublittoral fringe) up to 1 metre wide. A vegetation profile down to 27 m in an area of extreme roughness at Lands End is given in Figure 7. 114 S. A. SHEPHERD ann IT. B, S. WOMERSLEY “" Cystophora intermedia & Corallina spp Ze Gellidiurm qlandulaefotium ¥- Curdiea gymnogongrades Melanthalra Spp. Mie Bs . Scytathalia dorycarpa Sp-------~-4 3 XG - Ecktonia radiata Ee e ted algae aa at werd SL Fig. 7. A vegetation profile near Lands End (very rouvh), Three belts in the upper — sublittoral are indicated by broken lines on the right of this zone. 20 lower ved Pyura pachydermatina A, £5 bryotvans € it y c+ Sponges Upper Sublittoral Zone (to 8-5 m deep) A strong surge exists down to at least 12 m and it is seldom possible to examine underwater the region just below low water level. The zone is: clearly defined and extends vertically down to between 3 and 5 m according to the degree of water turbulence, Along the western shore, on sloping faces, the zone contains three distinct horizontal belts. (1) The uppermost is colonized by Corallina sp, and cncrusting lithothamni: down to 1 m. Pterecladia capillacea occurs where there is local shelter near Restless Point. The corallines form a community with the barnacle Balanus nigrescens (Lamarck) and the -chiton Poneroplax costata (Blain- ville). Occasionally, the mollusc Dicethais textiliosa (Lamarck) is also seen. The upper limit of the belt is indicated by Cystophora intermedia which, on horizontal rocks, forms a dense conimunily but on sloping racks occurs only in scattered chimps. This community also cxtends above Cystophora irtter- media to form the lower eulittoral zone (see Womersley and Edmonds 1958 ) and it is now apparent that on such rough coasts there is a fairly uniform coralline mat—Balenus association extending for some distance above and below the low tide region (through and beyond the ‘suck back’ region) with a superimposed belt of Cystophora intermedia ocoring where it is subject to momentary emergence at low tide, (2) Below the corallines, there is a well defined middle belt comprising a mat chiefly of Geliditan yvlandulaefolium and Curdiea gymnagongroides, This mat extends to the lowest part of the zone but in its lowest 2 m tends to be overshadowed by more prominent species of the belt below, ENVIRONMENTAL FEATURES AND ALGAL ECOLOGY 115 (3) The lowest belt is characterised by larger algae, including Melanthalia concinna, M. obtusata, Sargassum bracteoloswan, Zonaria sinclairit and occasionally Scytothalia dorycarpa, and forms a transition zone to Use mid sublittoral zone dominated by Ecklonia radiata, The stalked ascidian, Pyure pachydermating (Herdman) var. gibbosa Herdman is common below about 2m, Where the rock face drops vertically into the sublittoral and on much of the steep and shaded southern shore, three distinct belts are not evident, Probably dlue to the lower light anreaaty, corallines are scarce and the upper sublittoral is dominated by Gelidium glandulaefolium, Curdiea gymnogongroides and Zunaria sinelairii, Lower down in the zone, purticularly on steep faces, Plocaurium angustum, Rhodymenia australis and Pterocladia lucida may uccur in addition ta the prominent species of this level referred to previously. Mid Sublittoral Zone (5-15 (-19) m deep) The upper boundary of the zone is sharply defined by the appearance of the laminarian Ecklonia radiata which dominates the zone and extends even inte the lower sublittoral. Eoklonia is co-dominant with Melenthalia spp. and other brown algae at upper Jevels of the mid sublittoral where they form a dense canopy, (See Lcklonia-Melanthalia Community where the species ace listed), Where agitation of the water is most severe, the undergrowth is sparse and in many places the rock is covered with a crust of lithothamnia, Below abont 10 m some minor changes in the vegetation occur. Brown algae (except Ecklonia) become sparse and a red algyl undergrowth occurs under the canopy of Ecklonia, Toward the lower limit of the zone, Lcklonia hecomes scat- tered and the red algal element increases. There are na noticeable qualitative differences between the vegetation on vertical and on horizontal surfaces where the surge is active, ie, to about 10 m depth on the rough shore (A), decreasing to abuut 1 m in the sheltered parts of Region B. Hawever upper-storey species Giniainly brawn algae) are less prominent while under-sturey species are more conspicuous on vertical than on level surfaces. With increasing depth (over 10 m) brown algae disappear rapidly from vertical faces and a red alga) community is established, usually epizvic on a ground commu- nity of calcareous bryozoans (mainly Reteporidae). Some algae appear restricted to or have a strong preference for vertical faces. These are Cheilosporum elegans, Epiphloca bullosa, Thammoclonium dichotomum, Laurencia clavata, L. eleta and L. filiformis. Lowey Sublittoral Zone (17-29 m deep) The oceurrence of 2 uniform red algal community in this zone is disenssed in detail later. Red algae form a dense cover on upward facing rocks but on steep slopes dre sparse (Figure 11). Here the tough and wiry algae of shallow water are replaced by delicate, filamentous or flabellate species. Near the base nf the island al 25-28 m, algae are sparse and the rock face is covered by sessile Fauna, Large sponges, the ascidians Herdmania momus (Savigny) var, granrlis Meller and Styela etheridgii Herdman are prominent. Bryozoan colonies of Hetepara spp. and Adeona grisea Lamouroux are abundant in places and provide a sub- strate for some algae e.g, Thamnoclonium dichotomum and Plocamium spp. Less prominent hut quite common are stands of the hydroids Plumularia procumbens Spencer, Sertularella lefa Bale and oveasionally Thecocarpus divaricatus Bale; orange and white gorgonians. crincids and crustacea are abundant, 118 §. A. SHEPHERD xp H. 8, S, WOMERSLEY (IL). REGIONS B AND C (MODERATELY ROUGH WATER) These are regions-of constant surge but lack the extremely rough conditions of the southern and western shorcs. Toad IIcad and Restless Point are the natural outer boundaries of the two regions as they mark the transition in the mid sub- littoral from communities of few species dominated by Ecklonia to those in which there is a more varied brown algal vegetation. Cystophora intermedia disappears from the sublittoral fringe at about these points aud is generally absent in regions B antl C. Communities of green algac are common in more sheltered parts, At the inner boundaries respectively (Point Gillian and Penguin Kock) the wealth of algae decreases markedly, Due to the shallower depths in the two regions a lower sublittoral zone is generally absent. Upper Sublitteral Zone From Toad Head northwards towards Penguin Rock the upper sublittoral decreases from 3m broad to less than 1 m; it is occupied by a short and dense algal turf with often a thin encrusing sponge us a basal matrix. Ulow lactuca is gotten common at the upper limit of the zone. In the rougher parts of the regions, the algal turf comprises a Corallina-Zonuria community towards its lower limit, or further up on vertical faces the following species are frequently secn: Malopteris funicularis, H. gracilescens, Lobospira bicuspidata, Areschougia laurencia, Ballia eallitricha (stunted). The lower limit of the zone is often not clearly defined and some species more characteristic of the mid sublittoral may occur, c.g. Cystophora moniliformis, C, subfarcinata, Scytothalia dorycarpa, Seirecoccus axillaris, Sargassum. verrucn- lastim, Placamium coslaluin. In more sheltered parts of the regions, the zone bears a Pterocludia capillacea assuciation descending for about 1 m until it merges with the vegetation of the mid sublittoral zone. Wowever, an Amphiroa-Corallina association is able to dis- place the mat of Pterocludia in a sunny aspect and in well-agitated water; in places, it dominates the slope from low water leyel to about 4m deep, Three communities of green algae are often seen. Between { and 2m depth Cuulerpa brownii occurs cither as a mouospecific community on horizontal rock surfaces or among the Amphiroa-Corallina community at the same depth, A little deeper between 2 and 41 u Cuulerpa flexilis community is common on horizontal rock faces, Occasionally a Caulerpa obscura conununity occurs at about 3 to 4m. Mid Sublittoral Zone In the upper part of the zone, a fucoid association forms a dense cover over the rocks, The preference of algae for upward faviny rocks with increasing depth has been described and is evident in this zone. The vegetation near the sublittoral base of the island is poor and limited to a few species of which the brown alga Clessophora nigricans is prominent. The poverty of algal growth is probably duc to the presence of fine sediments on the rocks as is indicated by the common vecurrence of the bulky ascidians Herdmania momus var. grandis and Ascidia sydnepensis Stimpson. (111). REGION D (ABALONE COVE) The depth of water is limited ta 5 m and there is a general decrease in the nwuber of species compared to other regions; the lower sublittoral zane is not present. ENVIRONMENTAL FEATURES AND ALGAL ECOLOGY 1l7 Upper Sublitioral Zone This is very narrow (0-0-5 m) and is represented only by a dense mat of Pterocladia capillacea, At the boundaries of region D, where wave-actinn increases slightly, corallines are more in evidence and tend to displace the Pterocladia mat. Mid Sublittoral Zone Part of this area has a solid granite substrate and the remainder has a Joose boulder slope with rounded stones up to 50 cm across. The vegetation varices according to the type of bottom, Small stones are unstable and do not support large brown algue. The solid rock bears a “forest” of Ecklonia (up to 80 cm high) with very few undergrowth species except for a thin crust of lithothamnia, Steep or vertical slopes, however, have small numbers of the following species: Halopteris funicularis, H. gracilescens, H. pseudospicata, Dictyota diemensis, Zonaria angustata, Z, crenata, Z, spiralis, Sargassum verruculosum, Cheilasporum elegans, These species are also common on all except the smallest stones of the boulder slope. The bright orange jointed bryozoan Catenicella margaritacea Busk is also conspicuous in this zone, At about 3 m depth Ecklonia is largely replaced by species common in the fucoid association, namely—Acrocarpia paniculata, Cystophora monilifera, C. moniliformis, C. subfarcinata and the coralline algae Cheilosporum elegans and Metagoniolithon charoides. Nearby, the sandy hottom supports dense beds of the marine angiosperms Amphibolis antarctica, A. griffithii, Posidonia australis (narrow leaf form) and Heferozostera tasmanica. Thexe sea-grass communities have not been studied in detail, (IV). ALGAL ASSOCIATIONS AND COMMUNITIES The associations and communities recognised about the island are deseribed below. Communities of the eulittoral zone were not specifically studicd and are only discussed where they extend into the sublittorul. A list of the commoner algac, from the four regions recognised and with known depth ranges, is given in the Appendix. 1. Coraruine Association Many corallines tolerate strong light and occur commonly in the lower eulittoral and upper sublittoral. At West Island corallines are not prominent on the steeply sloping and shaded southern and eastern shores but are common elsewhere. (u) Corallina community Corallina sp. Conditions: —Moderate to strong turbulence, Vertical Range:—Lower eulittoral dawn to 1 m. The community is well developed along the western shore of Region A, especially on horizontal or gently sloping rocks. The association with the bamacle Balanus nigrescens and certain molluscs has already been described (p, 114). This community extends into the lower eulittoral where Balanus may become dominant in some localities ies also described for Point Sinclair, Eyre Pen. (Worersley antl Edmonds 1958)). In very rough conditions the community appears as short tufted groups of plants scarcely 5 cm high, but in more sheltered places plants wre denser and may show a vivid pink growth ta abant 7-8 cm in height. 118 S.A. SHEPHERD ann I}. 1. S, WOMBRSLEY (b) Amphiroa-Corallina Community Common:—Amphiroa anceps, Corallina cuviert, Cheiloyporum elegans. Oecaslonal;-—Corallina sp, Conditions: —Moderate turbulence, Vertical Range: 0-5 m. This community is prominent in Region © atid portion of Revion D near Penguin Rock and in optimal conditions forms a very dense turf to about 10 em in height. Toward its lower limit, calcareous algal fragments accumulate among the living plants providing a haven for worms, crustaceans and molluscs. The proportions in which the component species ocevr may vary with depth as shown in Figure 13. Between 3 and 4 m, Cheilosporum elegans characteristically forms a pure stand on steep or vertical faces. Other species such as Carilerpa brownii, Pterocladia lucida and Melanthalia obtusata occasionally occur, This community is seen in similar habitats along much of the central Flindersian province uf southern Australia. (c) Corallina-Zonaria Community Common:—Zonaria sinelairii, Corallina cuvieri, Fairly eommon:—Sargassuwin bracteolosum, Cheilosporum elegans, Occasional:—Caulerpa brownii. Conditions:—Moderate turbulence. Vertical Range: 0-3 m deep. The community is well developed in moderately rough situations. It cousti- tutes the uppermost sublittoral zone in Region B andl also may be found in small stands in Region C. The development of Sargassum hracteolosum is seasonul: from February to Septeraber only the basal leaves are seen and the comm-nity is dominated by Corallina cuvieri and Zonaria sinclairti which forms a dense mat between 5S and 10 cm in height. In spring, Sargassum bracteolosum rapidly develops fertile fronds reaching 30 cm or more, then overshadowing the other components; these fertile fronds are completely lost again by February. With increasing turbulence, Corallina cuvieri and Sargassum bracteolosum become sparse so that in some places there is an almost pure community of Zonaria sinclairii. This is seen mostly on gently sloping rock where the water is well agitated, and the community may continve into the lower eulittoral. The following species are more commonly seen on steep faces or toward the lower limit of the community—lalopteris gracilescens, H. funicularis, Lobospira bicuspidata, Cheilosporum elegans, Areschougia dumosa, It is uncertain whether their preference tor a steep surface is due to a lower light requirement, « lower tolerance of surge, or both. 2, PaunocLapia CAPILLACEA ASSOCIATION Common:—Pterocladia capillacea, Fairly common;—Sargassum bracteo- loston, Asparagopsis armata, Plocamium angustum. A number of other species oceur but these are probably the outliers at communities lower down in the sublittoral. The following have been recorded ut yarious times buf are usually stunted in form and not common, Caulerpa flexilis, C, absoura, Dictyota diemensis, Zonaria sinclairii, Z. spiralis, Cystophera subfarcinala, Corallina cuvieri, Melanthalia obtusata, Laurencta elata. Conditions: —Slight to roderate surge, with a preference for steep or verlival faces, Where the surge is more severe the association is displaced by corallines. Vertical range: 0-2. m. ENVIRONMENTAL FEATURES AND ALGAL ECOLOGY ne) In Region D the association forms a dense turf between 5 and 10 cm high, down to about 1 m depth where it gives way to the laminarian Ecklonia, In Judith Cove (Region C) it may extend down to about 2 m where it is replaced by various brown algae, At very low tide the upper parl of the association is just emergent and in the summer the upper plants are often bleached by the sun. Corallina sp. occurs occasionally and Asparagopsis armata is often e iphytic on the Prerocindia, The community las only occasionally been noted elsewhere ty South Australia in similar conditions. 3. Geuinium GLaspunarronium—Curvis Gy xNocoNcROipEs Association Common:—Gellditin glandulaefolim, Curdiea “ymnogongroides. Wairly common:—Melanthalia concinna, M, obtusata. Occasiomal:—Zonaria sinelairit, Polyopes constrictus. Conditions—Ixtreme turbulence on steep faces, Vertical Range:—from 1 to 3m below low water. This association is present at Lands End below the Coralline Association. It is most evident ou steep or vertical rock faces, with the common species growing ip to about 8 em high. It forms a community with the barnacle Bolanus nigrescens und the stalked ascidiun Pyura pachydermatina var. gilbosa, Occasionally, a mixed Cerallina-Gelidiumn community is seen in pluces where the surge is strong but nol severe, With increasing depth, the associatian becomes subordinate ta the brown algae Ecklonia and Seytothalia, 4. Fucom Assocration Common:-—Acrocarpia paniculata, Cystophora monilifera, C. monilifermis, C. platylobium, C, subfurcinata, Seirococcus axillaris, Aspuragopsis armata, Fairly commoni—Scytothalia dorycarpa. Occasional;—Perit}-alia cauduta, Ecklonia rudiata, Sargassum hracteolosum. Conditions:—Moderate surge. Vertical Range: 3-18 m deep (in calmer situations 1-10 im deep). A dense vegetation of fucoid algne is a characteristic feature of rocky sub- strates un moderately rough shores of southern Australia: this community occurs throughout Regions B and C, and on some coasts in Sout Australia teaches to low tide level. The structure of the association is complex; its vegetation is usually two- layered, but occasionally three-layered, The dense upper layer, ranging from 50 cm to 1 tn in height, is dominated by fucoids, the individual species of which may oceur in stands up to 10 m? in area, or sometimes as single or small grnups of plants, The dissected and irregular nature of the rock surface on which the vegelution occurs creates nimerous microrabitats with differing light and surge, resulting in a complex mosaic. Different species tend to be dominant at different depths. Figure 10 shows the vertical range of some specics in Region B. Ecklonia radiate is surprisingly sparse, being absent from most level surfaces but present on stcep faces just below the lip of al-topped rocks. In deeper water of is to 20 m, Ecklonia persists in a predominantly red algal community. The middle layer is less complex; its height is from 10 to 20 em and indi- vidual plants generally lic seatlered and hidden rnder the shade of the prominent fucoid algie, At 5 m the undergrowth is mostly Cheilosporum elegans; at 8 m, Zonaria spp. Corallina euviert, Ualopteris spp., Plocamium angustumt and Phacelocarpus labillardiert occur, Between 10 m and 18 m the following species camprise the imdergrowth; Lobospira hicuspidata, Zonaria spiralis, Asparagopsis 120 5. A. SHEPHERD axp H. B.S. WOMERSLEY i= e oe Fy ‘= a <= - 8 a, 63 2 22 ee 5 ry a 2 “ £2 5 sn 2 4 RASB nu Sa SSB Ba eD a s ef es _ Se eset a RSPR ES PER RATS EES TERRE RES 24 2RBLPLESPEF ITA SES TET RE 2 PES ER REE EER ES EAR 5 “G3 33 PEBUM EPP DS “ 3 o Suki @aZeE mewtseg Sgt BF ZE $244 eSLEAL sme eee yg - aS Bee ewaenme = a eo a = Mey = o 5 = y =e a aittn 4 eenre F a a | arpa 2 FPRBERe BE ns cv. ‘eres => a Boanp tie? > 8p as SREESERLTLS Et RSESE ES ERS FS ERZ2 SE SEER, SEER EPEC SR ETE LEP SEER ER EPEEE EEE TEES Eee RP ESSEC ST RZ SRB SER ES EST ERE RCS TT ERE SEE TIES x oa > a-secfpomtwste = Er, aA eBe Fe owe vee Use Swe SBR A S aq BE SSeS lagpetert 23 Sa zo es E Be see =f 3s 58 tate tT ek EEF GST A PHU eC ee see se eT rere iagu st BSeSoa gp dtd hah Sete R tees zaezroec ee ow eeeeee eee ' \ ' ' i ey wamam=s =z- rama Fig. 8 Vertical range cif some common algae on horizontal rock in Region A (rough). — common (shown by a thicker line where dorminant); -——— —— ocea- sional; .. 2.5... Tare, armata, Peyssonelia gunniana, Phacelocarpus labillardieri, Plocamium angustum, P. mertensii, Rhodophyllis multipartita, Areschougia dumosa, Mychodia hamata and Osmundaria prolifera. At 18-20 m deep, the upper layer comprises mainly Ecklonia and Cystophora platylobium and is much less dense than in shallower water, On many slopes stands of Plecamium spp, are well developed. Here also a ground layer of pros- trate species occurs, c.g. Peyssonelia gunniana, P. novae-hollandiae and Sondero- phycus australis. With increasing shelter there are minor changes in the association. Some species become more common, e.g. Sargassum verruculosum, Corallina sp.,, Metagoniolithon charoides and Metamastophora flabellata. Figure 15 shows the horizontal distribution of some of these species. In Region C where similar surge conditions exist, the vegetation patterns typical of the wpper part of the association in Region B are seen. The under- growth species are mainly Metamastophora flabellata, Metagoniolithon charoides, Cheilosporum elegans and Corallina sp. Floristically, the association is very rich and the total number of species collected is about 80. 5. Ecxionta Rapiara Association Ecklonia radiata is one of the mast important and conspicnous zone-forming species of algae of southern Australia. [t is prominent at West Island where it dominates two habitats on the rough and sheltered sides of the island respec- tively. In each habitat, Ecklonia constitutes the bulk of the vegetation (Figures 9 14). In Region A, it characterises a community in water 3 to 18 m deep and in the sheltered Region D it occurs from about low water down to 5 m. Each community will be discussed in turn. Why Ecklonia is not more comunon on the moderately rough shores of Region B is puzzling, It is possible that this laminarian may be unable to compete well with fucoid algae where conditions are optimal for their development. “NVIRONMENTAL FEATURES AND ALCAT, ECOLOGY 121 EeKlonia—Melanthalia community Common:—Ecklonia radiata, Scytothalia dorycarpu, Melanthalia concinna, Fairly common:—Acrocarpia paniculata, Sargassum bracteolosum, Melanthalia obtusata, Occasional:—Seirocacéus axillaris, Perithalia caudata, Undergrowth—Common:—Gelidium glandulaefolium. Fairly common:— Pterocladia lucida, Phacelocarpus Iuhillardieri, Plocamium preissianum. Occa- stonal:—Zonaria sinclairii, Corallina sp., Polypes constrictus, Callophycus laxus, Ballia callitricha. Conditions;—Strong to extreme surge. Vertical Range:—4-10 (-14) m deep. The species listed are all able to’ stand extreme water movement, The structure of the community is two-layered. The upper layer consists of Ecklonia, Scylothalia, Seirecoccus and Acrocarpia. Under these plants, un understorey of algae growing to about 20 em in height occurs. The turbulence is too great for most animals except Pyura pachijdermatina var. gibbosa and compound ascidians which colonise stecp faces, The vertical ranges of the algae are shown in Figure 8. Ecklonia community Eeklonia radiata and encrusting lithothamnia. Conditions:—Slight continuous surge. Vertical Range:—0-4 m deep, Very dense stands of Ecklonia occur on firm granite substrate, Undergrowth species aro absent except for the presence of pink encrusting lithothammia on the rock. Both Ecklonta and the lithothamnia preter well-agitated and sediment-frec water and conditions are no doubt favourable where the swell passing aronnd each side of the island causes intersecting wave patterns and a consequent con- tinual water movement (Figure 4). 6. OsmuNpDARIA PRotirerRs AssoctATION Common:—Osmundaria prolifera. Fairly common:—Cystophora monilifera. Conditions: —Moderate surge. Vertical Range:—3-8 m deep. Although this association is relatively common in deeper sheltered waters of St, Vincent Gulf, it is poorly developed at West Island and oceurs in only a few places in the more sheltered parts of Region B, The association has a simple structure and is dominated by Osmundaria prolifera with Cystophora monilifera as 2 characteristic associated specics. 7. Rep ALGAE AssociaTION Common:—Nizymenia australis, Rhodophyllis membranacea, R. multipartita, Plocamium angustum, P. mertensii, Rkodymenia australis, Ballia mariana. Fairly common:—Sonderaphycus australis. Occasional:—Gelidium australe, Pteracladia lucida, Peyssonelia gunniana, Thamnoclonium dichotomum, Avreschaugia dumosa, Ballia callitricha, Haloplegnw preissii, H ypoglossum. protendens. Rare :;— Cheilosporum elegans, Phacelocarpus labillardieri, Osmundaria prolifera. Conditions:—Reduced light and slight surge. Vertical Distribution: —16-28 m deep on horizontal and sloping rock, occasionally shallower (see below), $. A. SHEPHERD anv H. B, S. WOMERSLEY This association is developed in the deeper, quieter waters about the island, ie. in Region A and the outer part of Region B, The brown algae of the mid sublittoral gradually disappear between 10 and 15 m depth and are replaced by this community. However, Ecklonia may persist sporadically down to 24 m or more (Figures 7, 8, 14), In shaded aspects and in calmer microhabitats such as depressions in the rock, the association occurs at levels up to 10 m but is best developed between 15 and 20 m deep. The association is Horistically rich with 48 species recorded; plant cover is almost 100% with a two-layered structure. Some algae are com- monly up to 30 cm high and there is in places a low ground laycr of prostrate species—Sonderophycus australis, Peyssonelia gunniana and P. novae-hollandiue. 3 £33 ra = » 225 a 3 * € BS 2 > iz a2s*aan a fs e¢ & € € 7 & z 2 a w Soc = a Ww 5 as £ Bs 7 a 3 8 BE E88 & 5 Ss i] es s wie i = o mov zou a = ts & 0 eo £2 £2 FE FE ir} ft = wr er a o oa : i 9 Fy fa Fr Tt ; Ng \ / \ £ F bao v 4 | Fig. 9 Vertical dis- \ tribution of wet weight Ne of algae on horizontal - M surfuces between 5 ae and 27 m deep near E ‘ Seal Rock in Region A g kogm" (rough). The broken a8 ota line indicates total [ _seahed _ | weight of red algae. +s, E E 2 A = _ i S —p #& £3 7s a 2 3 a o £8 # aos = : 3 3 3 = 8 €>8 &§ Be Yo a » 3 o c = = - 3 a é £ € F EFF Tee F ee & : 3 my ae “a » of —_ 2 2 E i= bd t pm = 2 = 2 | u . 2 3 5 5 3g 25 £€ Esa ER £§ ? = 5 = ® . & & 2 5 £ 8 5 = oe o i) ‘ . § i bc} om 8 2 26 8 . 8 2 4 38 ¢ = = 2 a rr a e835 € 2322 82 Fs E = wo 4 Pi a a i=) oG & a o er 4 ov @ i= = lp ater | a UF \] | Ao: E at 3 \ <9 \ | C7 | . - } Tbs | ry \ t i H as y / | md \? [ \ ted \ a Nhao V po | mr " Vas | £ 7 : / cy a ratte \3 P E 6} 2 3 Y VF Auaien? vo @ $ ae seabed ie ant ' Fig. 10 Vertical distribution of wet weight of algae on horizontal surfaces between 2 and 18 m deep in Regi algae. ou B (moderately rough), The broken line indicates total weight of red ENVIRONMENTAL FEATURES AND ALGAL ECOLOGY 128 Individual species of the upper layer may occur from single plants to patches up to 1 square meter in area. It is uncertain whether the observed patchiness is chance or is caused by ecological factors, Bergquist (19602) comments on the same feature in New Zealand waters. In deeper water (over 20-22 m), plant cover decrcases to less than 10% as the fauna becomes dominant and covers the rock face. Frequently, algae in this region are attached ta bryozoa. The number of species also declines and at 25 m only L5 species were recorded, At this depth red algae grow only on the upper faces of rocks, the steep faces of which are covered entirely by sponges, gorgonia, corals; bryozoa and hydroids. Some algal species become heavily epiphytised by bryozoans, hydroids and sponges. Changes in the composition of the association with depth are shown in Figures 8, 9 and 11. Thamnoclonium sichotemum Plocamium preissianun, Phacelocerpus labillardierj Rhodaphyllis. membranacea Rhodophyllis multipartita TOTAL WET WEIGHT Rhodythenia australis Z £ ry 3 a = e 6 E > oo z s Fig, 11 Vertical distribution of wet weight of algae on ver- tical rock faces between 4 and 25 m decp at Seal Rock in Region A (rough), The shaded area repre- sents total wet weight of £cklonia radiata, which is not given as a separate diagram. 2- rtAatMm.o _ ut nn o eee SSS | Ballia ealtitricha wwamam = 25 8, CauLERPA Com™MontITIES Several species of Catulerpa are of common occurrence about the island. As their fronds rise from creeping stolons often densely intertwined, communities which occur in favourable conditions spread over extensive areas, Except where surge is strong, particulate matter accumulates among the stolons and probably prevents establishment of other algae. These communities are well developed on ee surfaces of rocks in agitated shallow water with maximal li ght conditions and are not uncommon in similar habitats elsewhere on the southern Australian coast. Caulerpa brownii community Conditions:—Moderate surge, Vertical Range:—Usually 1 to 1-5 m deep. Scattered plants as deep as 5 m. The species forms a dense community of plants up to 10 cm in height, in Regions B and C, usually on upward facing rocks. Sometimes scattered plants of Sargassum bracteolosum and Perithalia soudate oceur where the association is not donee. C. brawnii is also common in the lower eulittoral algal mat in Regions B and C. 124 5, A. SHEPHRRD axw H, BS, WOMERSLEY Caulerpa flexilis community Conditions: —Moderate surge. Vertical Range:—2-5 m deep. The stolons form a dense basal mat sheltering a rich crustacean. molluscan and worm fauna. Above it the fronds form a dense cover to ubout 15 em in height. At West Island the community prefers slightly deeper water than Caulerpe hrownii and is found in Regions B, C and D, Caulerpa obscura community Conditions: —Moderate surge. Vertical Range; —5-7 m deep. This community is common on horizontal or sloping rocks in Region B in rather deeper water than either of the other Caulerpa communitlics, The fronds are up to 20 cm long and area haven for very large numbers of amphipods and isopods, SEASONAL AND OTHER CHANGES Nearly all the prominent algal species (see Appendix) are present through- out the year, though some show pronounced scasoual growth. However data on many of the smaller species are not adequate to judge whether some rhight be strictly seasonal in oecurrence. Many red algae also appear to live for up to two years and show at least two age groups; younger plants are relatively free from epiphytes such us hydroids and certain bryozoans whereas older plants are often heavily epiphytised. Algal growth is vigorous from winter until carly summer, By midsummer the vegetation has an impoverished appearance as many species shed their fertile parts. The. following changes are comspicuous; Scytethalia dorycarpa and Seiro- coccus uxillaris lose some fronds and receptacles; Cystophora moniliformis loses its vamuli, leaving only the bare primary and secondary aves; the fronds of Caulerpa flexilis and C. brownii disappear leaving only their stolons on the rock face; the corallines lose fronds and ramuli often leaving bare stalks. During March, strong growth commences and the vegetation soon regains ifs winter appearance. As previously described, Sargassum bracteolosum grows scasonally during spring and sheds its fertile fronds by late summer (February). The growth of Ecklonta appears to cease during mid-summer and at this time the plants often lose part of their thalli while the remuinder is often grazed by the gastropod Subninella undulata (Solander). After completion of the raain part of this study some changes in the vege- tation were woliced during the summer of 1969-70. The density of Ecklonia greally increased on the boulder slope in Region }), where it had previously been sparse, and at a depth of 4 to 5 m Cystophora monilifera, which previously had occurred as scattered plants, formed deuse stands over one metre in height. The understorey species of smaller brown algae largely disappeared from this canopicd area and were replaced by a low mat of Corallina cuvierl and Corallina. sp. The brown alga Cladostephus verticillatus was noticed for the first time and became abundant in places. The winter of 1969 was free of storms and these changes are proray attributable to the calm conditions which had prevailed since the winter of 1868, Changes such as these will be followed over the next few years in order to judge the stability of the associations described im this paper. ENVIRONMENTAL FEATURES AND ALGAL ECOLOGY 125 ESTIMATES OF STANDING CROP In order to assess the individual contribution of species to the total biota, a quantitative study was made at selected localities on both horizontal and vertical faces. Over 100 samples were collected between August and December in 1967 and in 1968 by using a hoop of area 1/6 m® on horizontal surfaces and 1/10 m?2 on vertical faces, The hoop was placed on a rock and the algae were scraped from within the area into a net and later examined and weighed. Because of the physical difficulty in obtaining samples in strong surge where 10 minutes might be occupied for each, random sampling techniques were not feasible and the following procedure was adopted. A visual assessment was Rrst made of the locality to select a rock face on which the algac were considered to be Tepre- sentative of the average density and cover for that locality. Any rock face which appeared to he either unusually protected or subjected to extreme watcr move- ment was therefore ayoided, A number of contiguous samples was then scraped from the rock over a horizontal distance of several metres. This was repeated at various depths and localities. On vertical cliff faces a site fucing the direction of the swell was selected in each case to minimise local effects. At any single locality, 5 or 6 samples were considered sufficient to adequately sample the fairly uniform red algal growth (although often more were taken), but for the patchily occurring larger brown algae a more extensive area was sampled and a proportion of the plants collected. The method used by Crossett and Larkum (1966) is very similar. The results are given in Figures 9-14. At Seal Rock and at Toad Head samples were taken at approximately 3 metre intervals vertically, and in Judith Cove at one metre intervals, hodophyilis multipartita eyssonelia gunniena Thamnoclonium dichotomum Seirococeys axillaris Lobospira bicuSpidata Cheilosporum elegans Phéecelocarpua febillardier! Other rad algae TOTAL WET WEIOHT Nizymenia austrelis Pturocladia lucida as 3 3 2s = 2 i ES = u Ww pyro E P M 5 ! M . | Eo 1 a v) =a 10a Shs Fig. 12 Vertical distribntion of wet weight of algae on vertical rock faces between 3 sind 15 m deep in Region B (moderately rough), The shaded area represents total wet weight of brown algae. Since Ecklonia dominates the vegetation in the mid sublittoral in Regions A and D, estimates of density (number of plants per m?) and cover were also obtained, The results (Figure 14) show that the population density of Ecklonia is greatest (20+- plants per m*) at a depth of 6 m in rough conditions (Region 128 S. A. SHEPHERD ano H. B.S. WOMERSLEY E BS = rd Pm ir a3 es @ eck 7 Me ee Eee z 8& 48 G 6 e " o| uP | i J = i | } Fig, 13 Vertical distribution | of wet weight of Nb? | 4 algae in Amphiraa- 7 \ \ Corallina association E \ / in Region C, 1 ha ) ( 4 | -_ Lo \ \_} \ A) and at 2-4 m depth in Region D. In Region B the highest density values are at a depth of 4-5 m but are much lower (5 plants per m*), probably due to competition from other species. However, Figure 9 shows that the Bignest standing crop values (fresh weight) in Region A for Ecklonia occur at a depth of 10m, ic,, somewhat deeper than the depth at which the highest density values occur, This is hecanse the size and weight of individual plants in very rough conditions (ic. Region A, 5-6 m) is much less fhan in conditions where surge is moderate (the figures for mean pli weight being 95 ¢ for the former conditions as compared to 600-500 g for ess rough waters according to locality). Plants constantly subject to severe surge rarely develop to the size of those under less extreme conditions, and stipes with tattered or missing thalli are commonly seen after stormy weather, Fig. 14 Vertical ‘distribution — of plant deusity (as nurober of plants per square mete a Eck- . lonig radiata on N= horizeomtul — sur- namamMs 2- rta0MKo 0 plim? to pet SUAS r s 0 cover 50% faces in Regions A, Band D. DISCUSSION The decrease in surge from rough to sheltered shores of the island is accom- panied by conspicuous differences in the composition of the vegetation. The distribution of each specics depends upon its particular response to avid tolerance of various environmental factors. The survey has shown that groups of specics have similar distribution patterns resulting in the occurrence of plant communities which persist throughout an area so long as the environment remains substantially unchanged. The same communities are seen in other places where a similar environment recurs, At several points abrupt changes in the type of community ure also accompanied by a relatively steep gradient in surge or illumination, these being probably the two most important environmental factors. ENVIRONMENTAL FEATURES AND ALGAL ECOLOGY 127 TABLE 4 Showing the total number of species found in the various regions. U.8,E, — Upper Sublittoral; M.8.L. — Mid Sublittoral. L.8.L. — Lower Sublittoral. Green Algae Brown Algae Red Algae 4 ‘ . ‘ i A i x . , ne) HHA gs HAHA Ss i i waif a2 ean os | Bw SF | we ws fae pe 4H pe Ae Db 2 HH Bf Rough 1 — 1 2 3° 6 3 #9 6 25 48 65 76 Region A Moderately Rough 2 7— 7 38 24 — 24 2 60 — 61 92, Region B Moderately Rough 1 5 — 6 2 12 — 12 6 10 — 12 29 Region C Semi-Sheltered 1 6 ~— 6 1 16 — 16 4 5 — 6 27 Region D Total Number of Species 9 30 $3 132 extreme song thutarite slight Lerat, PUnee Caulerpa spp a Halopteris spp. r 5 PSS Sy Lobospira hicuspidala Zonaria angustata WI ! Zonaria crenata M | Zonaria sinclairii ; Zonaria spiralis e = Persthaiia caudata Seytothalia dorycarpa Seiracoceus axillaris Fig. 16 Elevation of the upper limits for some Acrocarpia paniculata Cystophera intermedia Cystophora = monilileca Cystophora = manilifarmis Cyslophora subfarcinata Sargassum bracteaiosum Sargassum verruculosum Asparagopsis armata Pterocladia capillacea Amphiroa anceps Cheilosporum elegans Metagoniolithon charoides Melanthalia concinna Melanthalia Phacelocarpus apedus obtusata 4 spe 1. cies with reduction in surge. Lobospira bicuspidata, Seirococeus axillaris, | Nizymenia australis, Rhodophyllis -multipartita, — BR. membranacea. Mychodea hamata, _Osmundaria prolifera, Laurencia clavata. Zonaria angustata, Zonaria spiralis, Asparagopsis armata. Metamastophora flabellata, Cheilo- spore elegans, Euptilota articu- ata, Thamnoclonium dichotomum. Horizontal range of common algae of the mid-sublittoral. Extreme to strong surge —Region A. Moderate surge—Regions B and C. Slight surge—Region D. 125 5. A, SHEPHERD ann 1. B.S. WOMERSLEY A feature of the survey is that comparatively few specics comprise the bulk uf mg vegetation while many species occur in small numbers or in a restricted caliny. Horizontal Distribution The total number of specics in the four regions yaries considerably and their distribution in regions and zones is given in Table 4. It is apparent that a shore of moderate roughness favours the greatest number of species; this Is due ta the oceurrence of two floristically rich communities viz. the Fucoid Association in the mid sublittoral and the lower sublittoral association of red algae. However, the latter association is better developed in the deeper waters of Region A where there is lower light intensity. Figure 15 gives the horizontal ranges of some common species, mostly af the mid sublittoral, and it is evident that water movernent is an important factor limiting the horizontal distribution of most algae to that parl of the shore where suitable conditions exist, Some shade-talerant species (see Figure 16) arc able to extend their horizontal range by growing at a greater depth in rougher conditions. Green algal (Cavlerpa) communities require rather sheltered conditions and ate distributed accordingly. Their occurrence at diferent depths probably reflects their particular requirements for light rather than for water movement, Vertical Distribution It must be re-emphasized here that this survey deals with the algae of horizontal and vertical or steeply sloping rock surfaces on 4 “steeply sluping® granitic island. These habitats are relatively uniform compared to those on cul- earvous coasts where rock platforms at about low tide level offer a yreat variety of pools and overhangs giving great diversity in microhabitat conditions of light and water movernent. On sick npick platforms (see Womersley 1948), many species recorded only from deeper zones (e.g. the mid sublittoral) on West Island ure tound in shaded or sheltered pool areas, At low tide, deep pools on rock platforms provide conditions of surge comparable to those at some depth, Changes in algal vegetation with depth have been documented for many seas (for recent studies see Crossett and Larkum 1966, Jorde 1966, Kitching 1941, Neushul 1965, Petrov 1967, Vozzhinskaya 1965, and Zaneveld 1966). Other workers have shown experimentally that important controlling factors are gradients in light and water movement (see Conover 1968, Feldmann 1937, Jorde and Klayestad 1963, Levring 1947, 1966, 1968, Whitford and Kim 1966), These factors will now be discussed] tur each zone. (1) Upper Sublittoral Zone This zone, best developed in Region A, is dependent on rough conditions (Figure 6), Sume species (Curdica gymnogougrvides, Melanthalia spp, and Polyopes constrictus) require high water movement and are restricted to this zoe; others tolerate these conditions and range more widely in the sublittoral e.g. Gelidium glandulaefolium, Pterocladia capillacea and Corallina spp). Strong hght és a limiting factor for many species, but some brown algae (Sargassum. bracteolosum, Zonarla sinclairii, Cystophora subfareinata and Acrecarpia panicu- lata) and coralline algae (Corallina spp, and Amphiroa anceps) withstand full sunlight and even grow in momentarily emergent situations (see p. 115 and Figure 7). Feldmann (1951) attributes the suecess of corallines in high light intensitivs ta the presence in their tissues of calcium carbonate which serves as a light shicld. This probably explains their abundance in sunny aspects about the island. ENVIRONMENTAL FEATURES AND ALGAE ECOLOGY 129 In rough areas of West Island the upper limit of the upper sublittoral zone is marked by the sublittoral fringe zone of Cystophora intermedia (Womersley and Edmonds 1958, p. 233) as shown in Figure 7. This fringe zone is absent on less rough coasts (Regions B, C, D) where the mid sublittoral large brown algal associations approach closer to low tide level. The lower limits of the upper sublittoral zone ave often indicated hy the tattered remnants of species characteristic of the zone below, suggesting that wave action prevents the encroachment of algae characterising the mid sublittoral by its destructive effect on these young plants. probably during storms, rather than by preventing their initial establishment. (2) Mid Sublittoral Zone The importance of surge rather than light in determining the depth at which an algal zone occurs is strikingly shown for the mid sublittoral zone. As shown in Figure 6, this zone is depressed in rougher conditions. In such cases surge conditions are of primary importance providing light intensities are still udequate for the species concerned. The mos? conspicuous alga of this zone, Ecklonia, grows to a considerably greater depth in Region A (Figures 9, 10 and 14) than-in the other regions, and in ather rough ocean areas of South Australia occurs at much greater depths (Shepherd, unpublished data). Other West Island species whose lower limit is similarly extended by greater water movement are Perithalia caudata, Gelidium australe, G. glondulaefolinm, Pterocladia lucida, Cheilosporum elegans, Thamno- elonium dichotontume and Nizymenia australis, On the other hand some species of algae do not grow at greater depth in rougher conditions (e.g. Acroaverpia paniculata, Cystophora moniliformis, C. ad and C, subfarcinata) and it is probable that light attenuation is the critical factor determining the lower limit for these species. Asparagopsiy armata occurs principally as an epiphyte, but shows little preference for a particular algal host (see Appendix). It is unable to grow in very rough conditions but is prolific elsewhere, At its lower limits the specles appears lo be sensitive to reduced water movement. On European coasts the species has a harrower vertical range but its ecology is otherwise similar (see Dizerbo 1964), A third factor which may be important in limiting the growth of some algae at depth is the nature of the surface film on the substrate. It has been observed that some algae (eg. Ecklonia, Scytothalia and Seirococcus) only grew on clean rock surfaces. In deeper water, with reduced water movement, the rock is covered with sediments of various kinds, Such a surface may be unsuitable: for establish- ment of these algae. This factor is clearly related to water movement and further studies are necessary ta elucidate it. (3) Lower Sublitteral Zone This zone is occupied by species which are adapted to low light conditions and slight surge. The decrease in light below 25 m, associated with turbidity near the bottom, is probably responsible for the disappearance of algae just below this depth. However, other factors not investigated may also have some effect: these include the deposition of sediment previously mentioned (see Strachan and Koski 1969) and the smothering effect of epiphytic bryozoans on some algae. The lower limit for attached algac for the waters of Encounter Bay is probably about 30m; further offshore, in deeper waters, the lower limit is known to exceed The Factory decet nang the upper limit for red algae are problematic and iC is not often possible to distinguish between the effects of light and surge. to 5. 4. SHEPHERD ano H. B.S. WOMERSLEY Rhodophyllis multtpartita and R, memlrranacea appear to be sensitive to hoth factors and are appreciably displaced upwards only with a combination of sheltered and shaded conditions (Figures 9-12). Some species appear to respond in the same way to reduced water moyement (see Figure 16). However, it appears that most species of the mid and Jower sublittoral are sensitive to strong light to some degree. Uplift of limits in shade has been noted tur Thamne- clonium dichotomum, Pterocladia lucida, Metamastophora flabellata, Ballia mariana and #. callitricha, Vhe last named species has a remarkable vertical rue and is able to grow in deep shade in the upper sublittoral in rough condi- tions. Standing Crop and Density The variation in standing crop values taken on lorizontal and vertical suttices (Figures 9-12) further illustrates the effects of light and water movement on algac, Om vertical surfaces where light intensity is 10-40% of that on horizontal surfiuwes at a viven depth (Table 3) there is a substantial reduction in the total weight of standing crop. This is due partly to changes in eommmunity structure and partly ta competition for space with faunal clements which predominantly colonise stecp or vertical surfaces. Comparison of standing crop values in Region A with those of Region B {Figures 9-12) shows that, execpt at upper levels (0-8 m, Region A) where mechanical damage by wave action is considerable, there ure higher standing crop values on both horizontal and verlical surfaces in the rougher locality. This is probably due both to the better conditions for growth pravided by increased water movernent and to assouiated effects permitting greater density of algae, such as the presence of a cleaner substrate and the depression of certain faunal species inta deeper water. In Region A the highest standing crop values for Eeklania are 10-4 kg/m? (at 10 m) and there are even higher valnes of 16-8 kg/m? in Region D at 3m depth. These values. are comparable with values for Laminaria. hyperborea forests on coasts about the North Sea (e.g, 11-1 kg/m? reported by Lining 1969, and 6 kg/m’, a mean of 59 surveys, found by Walker 1954), Floristie Aspects Vurther detailed collecting aroumd West Island would doubtless considerably exten! the total of 132 species of green, brown and red algae recorded in Tuble 4 (the commoner ones being listed in the Appendix). It ts clear however that certain groups or genera are conspicuous in the sublittoral while others are notably absent, In the Chlorophyta, only the genus Caulerpa is common (6 species and 3 reeugmised communities), In the Phaeophyia, the Dictyotales (especially species of Zonaria) and the Fucules are most conspicuous, though the only member of the Laminariales (Ecklonia) found on central South Australian coasts is eco- logi¢ally important. In the Rhodophyta, two genera of the Gigartinales arc strikingly common, both in species and occurrence; these are Plocamtum with § species and Khada- phyllis with four species. The Ceramiales are not widely represented compured to the Jarge number of genera and species found in southern Australia: this applies especially to the family Rhodomelacene. However, further collecting may well result in many additions of small species in this order, With the exception of the coralline algae (which reach the lower culittoral) ENVIRONMENTAL FEATURES AND ALGAL ECOLOCY 131 and some of the large brown algae which reach to low tide level, all the species recorded (see Appendix) are found only in the sublittoral. The general lack of algae above low tide level on South Australian coasts has been documented by Womersley und Edmonds (1958). ACKNOWLEDGMENTS We are gratcful to the South Australian Museum for provision of facilities on West Island. Leon K. Ernst, John O. Ottaway and others were diving companions on occasions, and their assistance is acknowledged, The hydroids, ascidians and bryozoa referred to in this paper were identified by Mrs. J. E. Watson, Dr, P. M. Mather and Dr, I. Vigeland respectively. Assistance from the Ansteditan Research Grants Committee, in the provision of technical assistance, is gratefully acknowledged by the second author, APPENDIX. ALGAL SPECIES LIST The following list includes the commoner species collected during the survey but not those found only rarely, Further collecting, especially in other micro- habitats than vertical and horizontal reck, would doubtless increase the number of species. Womersley 1956b and 1967 give references to the southern Australian species of Chlorophyta and Phacophyta respectively, but no single reference to the species of Rhodophyta is currently available, Specimens representative of all species are deposited in the Algal Herbarium, Department of Botany, University of Adelaide. The distribution of each species is given as in the four regions recognised (A, B, C. D), followed by the depth range in metres. References to text figures concerning the species are given where appropriate. Most species are present throughout the year, although some show their best development in spring and summer, CHLOROPHYTA ULYVALUS Ulva lactuea L. B, O-1; C, 0-1; D, 0-1. CAULERPALES Caulerpa brownii (C. Ag.) Endl. A, 0-3; B, 0-2; C, 0-2; D, 0-2. (Fig. 15), Caulerpa cactoides (Turner) C. Av. B, 5. Caulerpa flexilis Lamx. B, 2-5; C, 2-5; D, 3. (Fig, 15). Caulerpa geminata Harvey. A, 5; B, 8; D, 1. (uncommon). Caulerpa obscura Sonder. C, 3-7; D, 4-5. ( Fig. 15), Caulerpa scalpelliformis (R, Br.) C, Ag. D, 4, (uncommon). CopiaLEs Codinm pomoides J. Ag. A, 10-15; D, 5-7. (uncommon). PHAEOPHYTA SPHACELARIALEs—Stypocaulaccae, Halopteris funicularts (Mont.) Sauy. B, 3-6; D, 1-5. (Mig. 15), Halopteris gracilescens (J. Ag.) Wornersley. B. 3-6; C, 3-6; D, 1-5, (Fig. 15). Halopteris pseudospicaia Sauy, D, 3-5. (Fig. 15). Cladostephaccac Cladostephus verticillatus (Lightf.) C. Ag. D, 3-4. 132, S. A. SHEPHERD ano IH. B.S. WOMERSLEY DicrroraLes—Dictyoteae, Dictyota diemensis Kuetzing (narrow form). C, 1-5; D, 3-5, Dictyota prolifera Lamx, B, 15-22, Dilophus robustus (J. Ag,) Womersley. A, 10-13; B. 16. ( Fig. 8), Glossophora nigricans (J. Ag.) Womersley. A, 16-18; B, 10-22. (Fig. 8). Lobospira bicuspidata Aresch. A, 13-25; B, 6-25; D, 2-6. (Figs. 8, 12, 15, 16), (commonly epiphytic on Acrocarpia paniculata, Seirecoccus axillaris and Phacelocarpus labillardieri), Pachydictyon paniculatum (J. Ag.) J. Ag. B, 3-6; D, 3-5. Zonarieae Dictyopteris muelleri (Sonder) Reinbold. A, 13-25; B, 16-26. (Fig. 8). Zonaria angustata (Kuctz.) Pap. B, 13-22; D, 1-5. (Figs. 15, 16). Zonaria crenata J. Ag. A, 22; D, 3-5. (Fig. 15). Zonaria sinclairit H, & H, A, 0-5; B, 0-13; C, 0-3; D, 0-5. (Figs. 6, 15). Zonaria spiralis (J. Ag.) Pap. A, 1-3; B, 10; D, 1-5. (Figs. 15, 16). SPOROCHNALES Carpomitra costata (Stackh.) Batters. A, 7-25; B, 13-22. (Tig, 8). Perithalia caudaia (Lab.) Womersley, A, 2-14; B, 5-10; C, 2-3. (Figs. 8 15), LAMINARIALES Ecklonia radiata (C. Ag.) J. Ag. A, 4-22; B, 2-20; C, 1-5; D, 0-5. (Tigs, 7-12, 14), FucaLes—Seirococcaceae Scytothalia dorycarpa (Turn.) Grev, A, 2-17; B, 10. (Figs, 7-9, 15). Seirococcus axillaris (IX. Br.) Grey, A, 14-20; B, 7-25; C, 4-5. (Figs, 8, 10, 12, Jystoseiraceae Acrecarpia paniculata (Turn,) Avesch. A, 3-11; B, 3-15; C, 3-5; D, 3-5. (Figs, 8, 9, 10, 15). Cystophora intermedia |, Ag. A, sublittoral fringe. ( Figs. 7, 15), Cystophora monilifera |. Ag. B, 5-8; D, 1-5. (Figs. 10, 15). Cystophora moniliformis (Esper) Wom. and Nizam. B, 1-9; C, 3-5; D, L. (Figs, 10, 15 , 15), Cystophora platylobium ( Mert.) J. Ag. B, 10-18, (Fig. 10). Cystophora subfarcinata ( Mert.) J. Ag. B, 2-6; C, 3-5; D, 3-5. (Figs. 10, 15). Sargassaceae Sargassum bracteolosum |. Ag. A, 3-13; B, 0-10; C, 0-5; D, 0-2, (Figs. 10, 13, 15 Sargassum verruculosum (Mert.) C. Ag. B, 4-16; D, 2-3. (Figs. 10, 15). RHODOPHYTA NEMALIONALFS—Helminthocladiaceae Liagora harveyiana Zeh, B, 3-6 (uncommon). Bonnemaisoniaceae Aspuragopsis armata Harvey, A, 16-25; B, 6-16; C, 3-5; D, 0-2. (igs. 10, 13, 15, 16). (A common epiphyte on Zonaria spp., Acrocarpia paniculata, Cystophora monilifera, C. moniliformis, Sargassum verruculosum, Gelidium glandulae- folium, Pterocladia capillacea and Amphiroa anceps). ENVIRONMENTAL FEATURES AND ALGAL EGOLOGY 133 Delisea elegans (C. Ag.) Mont. A, 16-19; B, 13-16. Delisea hypneoides Harvey B, 13 (uncommon), Delisea pulchra (Grey,) Mont. A, 19-22 (uncommon). Leptophyllis conferta (R. Br.) J. Ag. B, 13-22. GELIDIALES Gelidium australe J. Ag. A, 3-23; B, 3-13, (Fig. 8). Gelidium glandulaefolium H. & H. A, 4-20; B, 6.10. (Figs. 7,8). : Pterocladia capillacea (Gmel.) Born. & Thur. B, 3-6; C, 0-5; D, 0-5. (Fig. 15). Pterocladia lucida (R. Br.) J. Ag. A, 4-22; B, 6-10 (Figs. 8, 12). “ CryYPTONEMJALES—Squamariaceae Peyssonelia gunniana J. Ag. A, 11-24; B, 13-22. ( Figs. 8, 12). Peyssonelia novae-hol landiae ( Kuetz. ) Harvey. A, 12-22: B, 12-18 Sonderophycus australis (Sonder) Denizot. A, 8-26; B, 13-22. Corallinaceae Amphiroa anceps (Lamarck) Dene, C, 2-5. (Figs, 13, 15). whedspyiein oF elenatie (H. & H.) Aresch. A, 8-23; B, 3-16; C, 1-3; D, 3-5. ( Figs. 8, 12, 13, 15, 16), Corallina cuvieri Lamx. A, 0-2; B, 3-10; C, 2-5; 2, 1- 2. (Figs. 7, 10, 13). Corallina sp, A, 0-3; B, 1- 3; C, 1-5; D, 25. (Figs. 7 3). The species of Corallina need detailed study; aa taxa may be present under C. cuvieri and the status of Corallina sp., possibly related to C, officinalis, needs clarification. Metagoniolithon charoides (Lamx.) W.v.Bosse. B, 2-6; D, 5. (Fig. 15). Metamastophora flabellata (Sonder) Setchell. A, 10-18; B, 7-13, rig. 16). Cryptonemiaceae Carpopeltis phyllophora (H. & H.) Schmitz. A, 10-18; B, 6-13. Epiphloea bullosa (Harv.) Schmitz? A, 10-16. Polyopes constrictus (Turn.) J. Ag. A, ‘9. 6; D, 0: Phare elomtven dichotomum (J. ‘Ag. ) J. ‘Ag. i. "13.98; B, 10-13. (Figs, 8, 11, 12, 16 GicartTinaLes—Gracilariaceae Curdiea gymnogongroides J. Ag. A, 1-8; C, 2-3, (Figs 7, 8). Melanthalia concinna J, Ag. A, 3 ae B, 3-12. (Figs , 8, 9, 15), Melanthalia obtusata (Lab.) J. Ag. A, 6-16, B, 6- 105 , 12. (Figs. 7, 8, 9, 15). var. intermedia (Hary,) J, Ag. A, 16-18; B, 6-10, Plocamiaceac Plocamium angustum (J. Ag.) H. & H. A, 3-28; B, 2-22. (Fig. 8). Plocamium coccineum ( Huds.) Lyngbye. A, 14-26; B, 10-15; D, 2. (Fig. 8) Plocamium costatum (C. Ag.) Il. & TH. A, 15-20; B, 6-10. (Tig. 8). Plocamium dilatatum J. Ag. A, 15-20; B, 10-16. (Fig. 8). Plocamium leptophyllum Kuctzing, A, 90-24: B, 16-20, Plocamium mertensti (Grev.) Harvey. A, 10-25: B, 6-16, (Fig. 8). Plocamium patagiatum J. Ag. A, 10-25, (Fig, 8). Plocamium preissianum Sonder. A, 3-17; B, 10-20 (Fig. 8). 134 5, A. SHEPHERD anp IT. B. 8S. WOMERSLEY Phacelocarpaceac Phacelocarpus apodus J. Ag. C, 2-5. (Fig. 15). Phacelocarpus labillardieri ( Mert.) |, Ag. A, 5-26; B, 6-15. (Figs, 8-12). Nizymenia australis Sonder. A, 13-25; B, 6-16. (Figs. 8, 11, 12, 16). Solieriaceae Callophycus laxus (Sonder) Silva. A, 10-20, (Fig. 8). Rhabdoniaceae Areschougia dumosa Harvey. A, 16-24; B, 13-16. (Fig. 8). Areschougia laurencia (H. & H.) Harvey. B, 6-10. Rhodophyllidaceae Rhadophyllis marginalis J. Ag. B, 13-18. ene membranacea (Ii. & H.) Harvey. A, 13-26; B, 10-23. ( Figs. 8, 9, 11, 16). Rhodophyllis multipartita Harvey, A, 10-26; B, 6-23. (Figs. 8-12, 16). Rhodophyllis ramentacea (C. Ag.) J. Ag. A, 13; B, 13-18. Hypneaceae Hypnea episcopalis H. & H. A, 16-18; B, 6-16. Mychodeaceae Mychodea hamata Uarvey. A, 15-18; B, 6-8. (Fig. 16). Ectoclinium latifrons J, Ag. A, 13-17. Acrotylaceae Acrotylus australis J. Av. B, 6-13. Peltasta australis J. Ag. A, 10-16; B, 13-16. RHODYMENTIALES—Rhodymeniaceae Rhodymenia australis Sonder. A, 13-26; B, 13-23. (Figs. 8, 11). Champiaceae Champia tasmanica Harvey. A, 16-22. CrRAMTALES—Ceramiaceae—Crouanicae Gattya pinnella Harvey. B, 16-21. Antithamnieae Acrothamnion preissii (Sonder) Woll, A, 16; B, 6-13. (Epiphytic on Gelidium australe, Pterocladia lucida, Nizymenia australis and Ballia callitricha), Ballia callitricha (C. Ag.) Kuetz. A, 5-25; B, 5-23, (Figs. 8, 11). Ballia mariana Harvey. A, 10-26; B, 13-26. (Fig. 8). Spongoclonieae Haloplegma preissii Sonder. B, 16-26. Spongoclonium sp. A, 13-20; B, 18-26. Other species of Spongoclonium occur at Toad Head and Oedipus Point in 40-36 m. The species of this genus are confused and await monographic study, ENVIRONMENTAL FEATURES AND ALCAL ECOLOGY 135 Griffithsieae Neomonospora elongata (Harvey) Womersley. A, 19-26; B, 13. Neomonospora griffithsioides (Sonder) Womersley. B, 6-23. Spyrideae Spyridia opposita Harvey. A, 15-20; B, 10-13. Ptiloteae Euptilota articulata (J, Ag.) Schmitz, A, 10-20; B, 6-23. (Figs. 8, 16). Delesseriaceae-Hypoglossum group Hypoglossum protendens J. Ag. A, 16-26; B, 13, ( Fig. 8). Hemineura group Hemineura frondosa (H, & H.) Harvey. A, 16; B, 19-26, Phycodrys group Crassilingua marginifera (J. Ag.) Pap, A, 10-19; B, 13-16. Halicnide similans J. Ag. A, 16-26; B, 16-22. Cryptopleura group Acrosorium uncinatum (J. Ag.) Kylin. B, 19. Common as small plants on other algae in various depths of A and B. Hymenena multipartita (H. & H.) Kylin A, 13-26. Dasyaceae Dasya ceramivides Harvey. B, 16-26, Heterosiphonia australis (J, Ag.) De Toni. A, 21-26. Rhodomelaceae—Polysiphonieac Polysiphonia nigrita Sonder. B, 3-10. Epiphytic on Acrocarpia, Scytothalia and Cystophora subfarcinata. Amansieae Osmundaria prolifera Lamx. A, 18; B, 5-22. (Fig. 16). Laurencieae Laurencia clavata Sonder? A, 13-26; B, 6-23. (Fig. 16). Laurencia elata (C. Ag.) Harvey. A, 6-10; B, 13; C, 1-2. Laurencia filiformis (C. Ag.) Mont. B, 6-23, REFERENCES Bennett, Isoner, and Pore. 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Rep. 1965, 57-61. 134 5. A. SHEPHERD ano HB, 5. WOMERSLEY Dizerno, A, H., 1964, L’ecolagie d’Asparagopsis armata Hary, ¢t de Falkenberuia rofolanose (Harv.) Schmitz dans le massif Armoricain. Prov, 4th Int. Seaweed. Symp.,, Biarritz, Sept. 1961, pp, 179-185. Enucsreis, T., Cuarciz, J, $., and McLacuian, J., 1969. Preliminury survey of the sublittoral Hora of Halifax County, J, Fish, Res, Bd. Canada 26, 2703-9713, FrLomann, J., 1937. Recherches sur la vegetation marine de la Merliterranee. La cote des Albores, Revue algol. 10, 1-339, pls. 1-20, map. Funomtann, J, 1951, Ecology of Marine Algut, in “Manual of Phycology” pp, 315-334. (Chronica Botanica, Waltham. Mass. ), BORee, g. Ke 1961, An underwater survey on the Lulworth Banks, J. mar, biol, Ase, U.K. Ciaten, 'I',, 1930, Epihioses of the Gullmar Fjord IL, Kristineberss Zool, Stn 1887-1927, Nr, 4, pp. 1-380, pl. 1-6, map. Hencremn, J. W., 1957. Classification of marine environments, in ~“I'reatise on Marine Ecology and Palaeoecology” Vol. 1. Mem. deol. Sou; Am. 67 (1), 17-27. : Woawerix, W.. 1910, The glacial (Permo-carboniferous) Moraines of Rosethy Head and King's Point, South Australia. Trans. R. Soc. S. Atst. 34, 1-12. Jones, W. E., and Demernorecnos. A. A., 1965, A quantitative approach to the exposure problem. Br. phycol, Bull. 2 (6), 516-17, Joves, W, E., and Deserrorovios, A. A., 1968. Exposure to wave action; measurements uf an ampertint ecological parameter on rocky shores on Anglesey, J. expl. mar. Biol, Ecol. , 46-65. Jornr, J., 1966. Algal aysnciations of a coastal area south of Bergen, Norwuy, Sursia 23, 132, jJonpr, I, and Kuavesrav, N,, 1963, The natural history of the Mardangertjord. 4. The ben- thoie algal vegetation, Sarsia 9, 1-99, Kain, Joawna M.. 1980. Direct observations on some Many sublittoral algae, J. mar, biol, Ass. i-K, 89, 009-630. Kinkwoon, L. F., 1967. Inorganic Phosphate, Organic Phosphorus and Nitrate in Australian waters, CSIRO Aust, Din, Fish, Oceanogr. Tech. Pap, No, 25, Kitemesc, J. A., 1941. Studies in snblittoral ecology, IH, Laminaria forest on the west quast of Scotland; a study of zonation in relation to wave action and illunimation, Biol, Bull, mar, biel, Lah,, Woods Hole. 80, 324-337. Lynne, T., 1947. Submarine daylight and the photosynthesis of marine algac, Guteborys K, Vetensk. O. VitterhSarnth. Handl, IV. Ser, B., 5 (6), 1-90, Lrvnixc, T., 1966, Submarine light and algal shore zonation. Light as an ecalayical Factor, Syn. rif. ecol, Soe, 6, 305-318, Leanne, T., 1968. Photosynthesis of some Marine Algae in clear tropical oceanic water. Botanicu mur. 11, 72-8), Limrse, K,, 1969. Standing Crop and leaf area index of the sublittoral Laminaria species aear Helgoland. Mar, Biol. 3, 282-286. McLean, J, H., 1962. Sublittoral ecology of kelp beds of the npen coast near Carmel, Calilornua. Biol, Bull. mar. biol. Lah., Woods Hole 122, 95-114, Muus. B. d . 1968. A field method for measuring “exposure” by means of plaster Palle. Sarsia J, 61-65. Namsiun, M.. 1965, Scuba diving studies of thu vertical distribution of benthic marine: plants Rat, Gothoburgensia 4, 161-176, Pints, |. Mi, 1967. “The Mediterranean Benthos.” Oceanogr. May. Biol. Ana, Rew. 5, 449-533 PéRds, |, M., and Picanp, J., 1949. Notes sonimiires suv le peaplernent des croltes’ sous-marines de tegion de Marseille Ce somni, Seanc, Sac. Bingeogr. 227, 42-45- Perrov. kK. M.. 1967, Vertical distribution of phytobenthes in the Black andl Caspinn Stas, Okeanologiya 7, 314-326, Poous, i. If, and Ares, W, BR. G., 1929. Photo-electric measurements of submarine illumina- tion throughout the year. J. mar, biol. Avy, U.K. 16, 297-324. SSrmUT ON, |, 1985, Vertical Zonation of littoral Alyae in Bolusliin, Acta phiylogeogr. suex 50, 85-11. Srmacuax, A. R,, and Koski, R. T., 1969. A survey of Alwae off Palos Verdes Vaint, California, Calif. Fish Game 55 (1), 47-52. Srarxrano, J. D. TL, 1958, Solar Radiation penctrating the acean.—A review of requirements, data and methods of measurement, with particular reference to photosynthetic productivity J. Fish. Bes. Bd Can. 15, 453-493. Sveupaure, IL UL, Joshiapn, M. W.,. and Fuesisc, BK. H., 1942. “The Ouvatns, Their Physies, Chemisty aml General Biology”, (Prentice Hall, N.Y,), Vaceiet, J, 1967. The direct study of the populations of underwater clitts and .cayes, Uruteruwutes Assoc. Malta. Rep, 1966-67, 73-76. ENVIRONMENTAL FEATURES AND ALGAL ECOLOGY 137 Vozzuinskaya, V. B., 1965. Distribution of algae along the shores of western Kamchatka. Okeanologiya 5 (2), 123-127. Watker, F. T., 1954. Distribution of Laminariaceae around Scotland. J. Cons. perm. int. Explor. Mer 20, 160-166. Wuirtrorp, L, A., and Kit, G, S., 1966. The effect of Light and Water Movement on some species of Marine Algae. Revue algol. 8, 251-4. Womenstey, H. B. S., 1947. The Marine Algae of Kangaroo Island, A general account of the algal ecology. Trans. R. Soc. $. Aust. 71, 228-252, Womenstey, H. B. S,, 1948. The Marine Algae of Kangaroo Island II, The Pennington Bay Region. Trans. R. Soc. 8. Aust. 72, 143-166. Womenstey, H. B. S., 1956a. The Marine Algae of Kangaroo Island IV, The Algal Ecology of American River Inlet. Aust. J, mar. Freshwat. Res. 7, 64-87. Womessey, H. B. S., 1956b. A critical survey of the marine algae of southern Australia, T, Chlorophyta. Aust. J. mar. Freshwat. Res. 7, 343-83. Ms stig et H. B. S., 1966. Port Phillip Survey 1957-63, Algae. Mem. Nat. Mus. Vict., No. 27, pp. 133-156. Womerstey, H. B, S., 1967. A critical survey of the marine algae of southern Australia. IT. Phaeophyta. Aust. J. Bot. 15, 189-270. Womenrs-ey, H. B, S., and Epmonps, S. J., 1952. Marine coastal zonation in southern Australia in relation to a general scheme of classification, J. Ecol. 40 (1), 84-90. Womenrsey, H. B. S., and Epmonps, S, J., 1958. A general account of the intertidal ecology of South Australian coasts. Aust. J, mar, Freshwat. Res. 9 (2), 217-260. ZANEYELD, J. 5., 1966. The occurrence of benthic marine algae under shore-fast ice in the western Ross Sea, Antarctica. Proc. 5th. Int. Seaweed Symp. Halifax, Aug. 1965, pp. 217-231, EXPLANATION OF PLATE Puare 1 Fig. 1, Aerial photograph of West Island showing Encounter Bay and Victor Harbor to the north east. (photograph A. R. Milne) Fig. 2. Aerial photograph of West Island showing the main localities. (photograph A. R. Milne) PLATE 1 S. A. SHEPHERD AND H. B.S. WomersLey ABALONE COVE is oe ad ya - B. ~ Me. JUDITH COVE ait eat cad nai ~ oO "xe LANDS. END se vu 4 OEDIPUS POINT THE SUBLITTORAL ECOLOGY OF WEST ISLAND, SOUTH AUSTRALIA. 2. THE ASSOCIATION BETWEEN HYDROIDS AND ALGAL SUBSTRATE BY S. A, SHEPHERD? AND JEANETTE E, WATSON Summary The association between hydroids and benthic algae has been examined at West Island in Encounter Bay. Thirty-eight species of hydroids (of which 17 are new records for South Australia) are recorded epiphytic upon algae. Of these, 17 species show preference for particular algal substrates to a striking degree while 5 other species of very common occurrence are less selective of substrate, each being recorded on at least 10 species of algae. Observations upon the nature of preferred and unfavoured algae suggest that some hydroid larvae are positively rugotactic, favouring rough, flat or depressed algal surfaces and avoid filamentous or mucus-coated species. The biochemical properties of some algae and the presence of a suitable surface film appear equally important so increasing the ecological possibilities of substratum preference by hydroids. Red algae (with 38 species) are a more favoured substrate than brown algae (with only 15 species). The most important factor determining the distribution of epiyphtic hydroids in the sublittoral is the presence of suitable substrate algae. At West Island, optimal conditions exist in the mid-sublittoral between 12 and 20 m on the rough windward shore, where there is a rich red algal flora; here, there is an abundant epiphytic hydroid fauna in terms of species and density. THE SUBLITTORAL ECOLOGY OF WEST ISLAND, SOUTH AUSTRALIA. 2, THE ASSOCIATION BETWEEN HYPROIDS AND ALGAL SUBSTRATE by S. A. SHepreapt ann Jeanette E. Watson® SUMMARY The association between hydroids and benthic algae has been cxamined at West Island in Envounter Bay. Thirty-eight species of hydroids (of which 17 are new revords for South Australia) are recorded epiphytic upon algae, Of these, 17 species show preference for particular algal substrates to a striking degree while 5 other species of very common ogowrence are Jess selective of substrate, cach being recorded on at least 10 species of algae. Observations upon the nature of preferred and unfavoured algae suggest that some hvdroid Jarvac are positively rigotactic, favouring rough, flat or depressed algal surfaces and avoid filamentons or tycus-coated species. The biochemical properties of some algae and the presence of a suitable surface film appear equally important so inwreasing the ecological possibilities of substratum preference by hydroids. Red algae (with 38 species) are 4 more favoured sul- strate than brown algae (with only 15 species). The most important factor determining the distribution of epiyplitic hydruids jn the sublittoral is the presence of suitable substrate algae. At West Island, optimal conditions exist in the mid-sublittoral between 12 and 20 m on the rough windward shore, where there is a rich red algal flora; here, there is an abundant epiphytic hydroid faima in terms of species and density. INTRODUCTION Reports upon the association between benthic animals and algae in the sub- littoral zone are rare. Rogick and Croasdale (1949) in the region of Woods Hole, U.S.A, and Ryland (1962) on the English Coast have noted the association of bryozoa and algae; Sloanc et al, (1961) has reported upon the fauna on algae in Lough Ine, Eire, Following the account of Kato et al. (1951), Nishthira (1965, 1966, 19672, 1967b, 19684. 1968b) studied the ecology of hydroids in the region of Asamushi, Japan, Detailed reports of this kind for Australian waters are lacking although fragmentary information about the algal substrate of hydroids may be found in the papers of Bale (1884), Bartlett (1907), Mulder and Trebileock (1911), ae (1937, 1988, 1942), Hodgson (1950), Ralph (1956) and Permycuick This paper is the second of a series of studies upon algae and their associated fauna about West Island, Encounter Bay. An account of the sublittoral environ- ment and of the algal distribntion at West Island is given by Shepherd and Womersley (1970). IIydroids attached to rocky substrates, or found among holdfast fauna are: not included in this study and will be the subject of a later paper by the second author. Notes are made upon the abundance, fertile seasons and ecology of the species found. Microslides of hydroids examined in this study are lodged in the National Muscum of Victoria, the South Australian Museum and held in the personal collection of the second author. } Department of Fisheries and Hauna Conservation, 183 Gawler Place, Adclaide, S.A. * National Museum of Victoria, Russell Street, Melbuurne. Victoria. Trans, R. Soe. S, Aust. (1970), Vol. 4. 140 8, A. SILEPHERD ann J. E. WATSON TABLE 1 Hydroud epiphytes on algae. o indicates new record for South Australia * indicates months when fertile colonies lound Jan Féb Ma? Apr May din Jly Ang Sen Oct Nov Dee F, CAMPANTLARITDAE Campanitaria urdbiptiin Mulder & Trebilock 1914 QO Campanulivia australis Stechuw 1924 Orthopyzis eaticulata (Hineks 1953), * Orthopyzis angulute Hate 114 oO * Obelia geniculate (Linnt. 1768) ) * Stlicularia bilabiata (Coughtrey 1875) O |] * *) & FP. §¥NTHECIIDAB Diphuasia euhcarinata (Busk 1852) Synthectum sp. ' F, LINEOLARIIDAE ; | : 1 Lineolavia spinulosa Hincks 1861 O F, HALECIIDARB red Sroresbia daidala Wataon 1969 O's! F, SERTULARIIDAB Stereotheca elongata (Laminicoux 1816) ak Oruteritheca uconthostoma (Bale 1882) a Amphisbelia yaintme (Thompson 187) “e Ambphishetia maplestonei (Bate 1884) Amphtabetia minutia (Bale 1882) Amphishetia pulehella (Thompson 1874) Sertudaria aevute Stecherw 1921 Sertularia gertimita Bale L684 Sertwaria mecallumi Bartlett 1907 Sertdaria macrecatna Bale 1884 Sertularia obliguénode Mulder & ‘Trebilock 1944 Symplectoscyphus neglects (Thompson 1879) % | Me | | HR) Sy mplectoseyphua indivisus (Tale 1882) | % Sumplectnseyphus macrothecus (Bule 1892) oO \ Sertularelia robusta Conphitrey 1875 Dynamenda quadridentate (Elis & Solander 1786) i 000 0 0 oa F. PLUMULARIIDAR Anlennella sp. Llumularia alata. Dale 1888 Plaomularia flexuosa Bale 1894 Plumularia spinulosn var, spinosa Bale 1882 Phomedoria filicaulig Kirchenpatier 1876 Halopieris aylaophentiaformis Mulder & Trebileoek 1909 | © * Huycnotheca producte Rule Ta 4% Aylanphenia plumosa Tale 1882 ; Vherocarpne ihvaricatus var. mcoyt Tale 1RA2 Q Hulicornaria langirestris ( Kirchenpaver 1872) Halicornaria aseidinides Bale La84 Qo Hulicornopais elegans (Lamarck 1616) oo oO IIIT METHOD Algae collected ut approximately monthly intervals during the algal survey of West Island in 1967 and 1968 (Shepherd & Womersley, 1970) by the first author were examined for the presence of hydroids, and observations were made upon their fertile season. The algae were identified by the first author, and in cases of difficulty, by Dr. H. B. 8. Womersley, and hydroid determinations were made by the second author. In addition, algae collected early in the survey in 1965. and 1966 and mounted on herbarium sheets in the Botany Department of the Uni- versity of Adelaide, were examined by us. Although this material was dried and pressed, it was not difficult to recognize most hydroids. A few species required reconstitution in water before identification was certain, and only Antennella sp. and Synthecium sp. could not be identified to species. In this way, the common HYDROIDS AND ALGAL SUBSTRATE 141 species of algac were examined on numerous occasions and uncommon species were checked several times. Abundance of hydroid growth was cstimated subjectively by taking into account frequency of occurrence and luxuriance of spread of a colony upon a substrate. This method was found satisfactory as growth was either profuse and occurred on a majority of plants of an individual species or was only occasionally or rarely recorded. Hence the results, based upon a large number of observations at all times of the year give a good overall picture of the incidence of epiphytic hydroids. Nevertheless, it is possible that further collecting will produce addi- tional records as the abundance of some hydroids was found to vary seasonally and from year to year. RESULTS AND DISCUSSION The epiphytic hydroids and the months in which they are fertile are recorded in Table 1. Athecate hydroids were not found growing on algae probably because the unprotected hydranth is unable to withstand turbulent conditions. Same hydroids, listed in Table 2, were found on very few occasions, so that their constant association with particular algac is not established; it is likely that some of these hydroids occur on other substrates as well. The hydroids listed in Tables 3 and 4 are all associated with particular algae and the resnits show that these hydroids are selective of substrate in varying degrees, They are discussed in three groups, according to the degree of selectivity, The authors of hydroid species are giyen in Table 1 and the authors of the species of algac from West Island are given by Shepherd and Womersley (1970). (a) Species showing least selectivity The species in this group are: Amphishetia minima, Campanularia australis, Plumularia filicaulis, Symplee- toscyphus neglectus, Stereotheca elongata. TABLE 2 Hydroids getdom found on algae Iydroid Arimphisbetia maplestanet Amphisbetia mtpuda Antennella sp. Campunularia ambiplica Diphasia aybearinatba Dynamena quadridentata Halicornuria ascilioides Halupleris aglaopheniafarmis Lineolaria spinalosa. Plumularia alate Plumularia flecuosn Pycnotheca producta Sertularia genvinata Sertularia obliguanoda Sumyplectoseyphus macrothecus Synthecium sp. Algal Substrate Plocaraium sp. Carpopeltts phyllaphora Pteroclatdia Lucida Seirovcoccus axillaris Crassilingua marginiferc. Laurencia filiformes Metamustophora flabellata Laurencia filiformis Plocamium. preissianum Rhodophyllis multipartita Carpapeltis phyllophora Rhorymerviee australis Aonarin spiralis Peyssonelia guuniana Rhodymenia australis Lourenvia eluta. Laurencia filiformia Acrocarpin paniculuta Gelidium australe Cystaphora subfarcinata Lanrencia filiformis —_——n nk eke 142 5. A. SHEPHERD ann J. E. WATSON TABLE 3 Showing hydroida associated with brown algae. vc. = very tommmon; ¢- = cammon; cece. = occasional | g i g/E|2 sia]? €/s]. 24 6s gs/e s/ 8 s/s]e & | = | Number of z 3 = z |e = = ty = I8 Blow ~ hydra Ss) B/E | ELE £ | S2/5)/32'38] 2) 3) 8 species z < & S| s Ss S/S a |e c ios S/2P/S, 3) B/S) 3) SF] S| S| S| associated s £ | = © cs !/ 3 'S - a ‘cl = ith 2. Z)/sl/t)sla s |} sel sia es with bis S/ Sl sl el] SBS) 2/2] f2/5 ]8)8)] 8,838 Ig = 5 = oS & 8 Sc Kes = = = = 2 = alga . = £ = > > we 4 & = S ae 1 =|8)|5 oan = Sil BF Ss} sll] ei ele S = S Se & i 3 = So Rl/F|/s is]. s BE/s/3|2) 2) 8)2 = Si Btlslfis eS )/S5 (/P]e)]/S/ 8 18 = =s/|/&is = = = >= 5 s } i= | = = = AIolRloTs]/aq}/h]a a il|al/S |\|R\l\al er Lobosnira bicuspidata: oae oct By Zonaria anqustiia oce act 3 Zomarin crenala we 1 Howarig sinclairit ae oce ‘onut 3 Honaria. spiralis ote 1 Pevithalia enudata. ace out 2 Ecklonia radiata ve 1 Acrocarpin peniewate ote ace oce ce | ose a Cystophore monilifera oce 1 Cystophora monilifarmis occ 1 Cystophora subfarcinata ye 1 Seylathalia duvyearpa ¢ 1 Seiracoceus acillaria e oce 2 Saryassuin braeteotasune ve | ote 2 Sargasaum rerrucilosun oce | one ore | oot 4 Nuber of species epiphytised by this 5 |6 1]. 1 1 ] 2 1 8 2 1 By 1 hiydreid | a These are the most common hydroids of the region and several factors appear to contribute to their abundance. Although they occur on numerous species of algae, they are preferentially associated with a few species some of which are very common in the sublittoral, with the result that there is an abundance of available substrate on which their Jarvae may scttle. The fact that three of them (A. minima, §. elongata and S. neglectus) are fertile for most of the year (Table 1) no doubt also contributes to their prevalence (cf. Nishihira, 1966). (b) Species showing most selectivity ‘Two species were observed in association with only one alga, and one species was observed in association with the two related species of algac, These ure:— Obelia geniculate with Ecklonia radiata Scoreshia daidala with Zonaria.crenata Silicularia bilabiata® with Scytothalia dovycarpa and Seirococcus axillaris In the first two cases, the association appears to be obligatory as these two hydroids have not been recorded in southern Australia on any other substrate. (See Womersley, 1967, p, 226; Watson, 1969, p. 115), However, Obelia geniculata * There is also a solitary record of Usis hydroid on Acrocarpia paniculata, TABLE 4 Showing hydroids associated wilh red algae bi | a | - : is S| | FA i ! \ | a = Ly c S18 | # tw Bs = 2 £8 £ 2) E> 4) . Number of sls es = $ 8 = S.e hydroid species E/S|S/E/B/ElS|S\a S/S] .] | 2] 2) sasosiated e\/2|s|z aes S/EIS/E) Ga sls 2, 3 | § | With this alga Z/2/3/2/5/F E/E) El) Els|B,2 Ss]elz B/E RS] s) So S/S] F121 E/E) $s |S) S51 8/2 S| S)E] ea]: 7 es ee SE S/Elelf s/ej2ls/8/$i's/ 21 3/s) S\S/SlS/E/2 8 2/2/88 Sle] ei SiS/3/ S151, 8 S/S] Sl Zl s\ SiS / E'S 3] $/2/ 5) 8/8/28) 8) 21 z/S/2/8/$8) 3! = 5/8] S/FiZ) SESE SiSlE/S|E/8 SiS 8 SlRA/SPSIR SAR a aly le atte ieee Lei — a |} Cabidittm australe | oun t aree! ore] e occordoc § FJelidium glondulaecfolium ace, | oce| ocr) 8 oct! 7 Pterocludio: tucida | ote Hue} i | pce} pec one! 7 “s tel | eS nee |_| ae t Corallina sp, | t i t Metamastiophiora flabellata | ‘i oee ove| | 3 Sowlerophycus australis | |oeG)oce | [ voce | 2 Peyssonelia yuaniana | oce 1 Curpopeltis phyllophara | ig ace Jee | 4 Pokjapes constrichs ! ote 1 Thamnoclonium dicholomum © flowy 1 Callaphyliis cnicinea oce 1 Melanthalia conecinned | dee! 1 Melanthalia. oblusulie ore |e 2 Phocelocarpus vpolue ove) i | r | 1 PP pt = 7 lL oi ~ Phacrtocarpus complanatus a ¥ ace i ia: Pee Le Talat Inna! Phacelocarpus labillandiert | ace) occ!oce o (doe yejoue) + ore) 9 —— ——-| —— a —_—!.___] U « ; ! A Nizyrienta australis G e¢ joce e ive © face}: 7 Catlanhyeus laerus | e ace] 2 Aresthougia dumosa ore ocd 2 Khidophyllia multipartita octe! foley dec oor 5 Plocamitem. angriasharm ace ove] 3 flee i Plocannuya eoceineun ace | ! 1 Plocomium costatum ace oc occ ane] i i 2 Placa mertanasii owe} ‘oct onc ace 5 Plocamium putigiatum och} are 3 Plocanrium preiasranium ous) -o i ace oecloce oo e& ore Ww Avrotulus australis oct! c 3 Rhody menia eustralis ore} oce| cout 9 — ——}-— Advathainnian preissiz. i! 1 —_ ——— —— + i Ballin ealtitriche | } L 1 Euptilota articulate i ove 1 Apoglassun laamonicun | c Bi Cnissiliogue naireinitera nee oec| 2 Hymenena multipartita Joe | 2 Laurenoia itary. ace | occ ocd! 6 Gu ¥ . | I Number of species opiphiytised aliajisiel4|7)aliulslie 6 by this hydroid j | SSS Reis * To this casé, the hydritid is psually spizoic on the sponge Callgap@egia ap. which enerusts the algal surface, 14 5S A, SHEPHERD axn J. E. WATSON and Silicularia bilabiata are recorded growing on Macrocystis pyrifera (1) Agardh in New Zealand waters (Ralph, 1956), and Obelia geniculata is reported wpon Laminaria digitata (Huds.) Lamour, on the British coast (Robins, 1989) and upon Symphyocludia latiuscula (Hary.) Yamada by Nishihira (1946) in Japanese waters. Evidently, preference for a particular alga is a local character- istic of both SiNcularia bilabiata and Obelia geniculata and varies over their geugtaphic ranges according ta substratum possibilities. (¢) Species showing some selectivity The remaining hydroids in Tables 3 and 4 are all found on relatively few species of algae, indicating that some are more favourable than uthers; however, only 5 spevies (Crateritheca acanthostema, Lineolaria spinulosa, Plumnnularia spinulosa var. spinulosa, Sertulurelle robusta anc Sertularia acuta) show a strong preference: for a particular alga. Algae as Substrate It is clear from Tables 3 and 4 that at West Island the red algac as a group are the most favourable substrate for hydvoids. Except for three species, brawr wlgue are generally. unlavourable and yreen algac never seem to hear hydroids, According to Nishihira (1966, 1967a, 19681) the physical and chemical nature of the substrate is of fundamental importance to hydroid larvac, Our observations are in agreement, Algae with Hat laminar thalli, concavities or rugoye surfaces are favoured substrate and nearly all red algae on which four ur more hydroid species grow have these physical characteristics. Of the brown algae commonly epiphytised, Sargassum bracteolusum has flat and somewhat rugose hasal fronds and Acrocarpia paniculata has a rough and warty stem. However, the aftractiveness of other algae without these physical qualities, e.g. Melanthalia spp, and Gelidium spp. which are mucus-coated or possess Anely divided ramuli may depend upon a positive chemotaxis among hydrvid larvae as reported by Nishihira (1965b). Conversely some physical and chemical characteristics of algae may be adverse to hydroids. Generally, filamentous or finely divided algae (e.g. Ballia mariana, Corynospora spp, Plerocladia cupillacea and Halopteris spp.) do not sarty hydroids. Nishihira (19672) attributed this. to the fact that the filaments of such algae wre smaller jn diameter than the larvae and stolons of hydroids, The yveneral absence of epiphytes on brown algae is probably due to the presence of tannic substances secreted by their tissues (Conover with Sieburth 1964, Sieburth und Conover 1965). These tannins possess antibiotic properties inhibiling scttlement of larvae on the alga, and are found in muny brown algae (Ogine 1962, McLachlan and Craigie 1964), Some red algae (e.g, Rhodophyllis membranacea, Haloplegma preissii and Upiphioea bullosa (?)}) also appear lo secrete mucus and this may tnake them unuttractive to hydroid larvae, Corallinaceous species (e.g. Corallinu spp,, and Ainpliiroa anceps) are also not colonised by hydruids, The oldest part of the thallus of an alga is generally colonised first. Ecklonia radiata, which grows at the transition zone between stipe and frond, is usually enlonised first on the distal part of the frond whereas red and brown algae which grow apically tend to be eailoniised first on the stem, Algae in their first season of growth are usually quite clean and this may be @ useful field method for aging some species. The evident prefcrenee by hydroid larvae for a substrate which has awed may be due to the acquisition by the blade of the alga of & suitable surface film (Nishihira 19f8b) or may be due to a seasonal variation or a decline in antibacterial uctivity by the alva (Sicburth and Conover 1965). [IYDROIDS AND ALGAY, SUBSTRATE 145 Distribution of Hydroids Tn general, the occurrence of epiphytic hydroids appears to be related to the availability of suitable substrate algae rather than to any dircet environmental effect. Hence, the distribution of hydroids aboul West Island is determined by the distribution patterns of its preferred substrates, For this reason, epiphytic hydroids are relatively scarce on the protevted lee shore of the island where brown algae are dominant, but are abundant in the mid and lower sublittoral zones on the rough windward side of the island where there Js a rich and varied red algal fora, as deseribed in detail by Shepherd and Womersley (1970), However, the distribution of three hydroids (Obelia geni- eviluta, Orthopyxis angulata and Orthopyxis caliculuta) is exceptional as they evenr only in fairly sheltered conditions although their host algae are more widely distributed. These species all libcrate free-swimming medusae and it is possible that species which reproduce in this way are not adapted to rough conditions. The abundance of epiphytic hydroids is greater in a shaded micro-habitat that on horizontal rock surfaces, and an alga growing on the former site is generally more heavily epiphytised than the same species growing in a situation which is better lighted. FAs. many of the records in able 2 are from shaded habitats, The increased abundanee of hydroids both in species and in density in shade may be due to a preference for lower light intensities or to Factors asso- clated with reduced light such as the increased growth of encrusting cpibiota on algae in these conditions, resulting in a more attractive substrate. ACKNOWLEDGMENTS We are graleful to Dr. H, B. 8. Womersley for many algal determinations and helpful criticism of the manuscript, and to the Director and Dr. B. J. Smith of the National Museum of Victoria for the provision of facilities and equipment. The casts of this shidy were met hy grants to each of us from the Trustees of the C.S.LB.O, Science and Industry Endowment Fund. REFERENCES Bare, W. M., 1884. Catalogue of the Australian Hydroid Zoopliytes. Aust. Mus. Syduey, Barrier, C., 1907, Notes ou Hydroid zoophytes, Geelong Nat. (2) 38, 6-66, pee rin M,, 1987, The Eydrovea of Lady Julia Perey Island. Proc, R. Sov. Viet. 49, (2), 364-37 1. RACER M.. pee. The Hydrozoa af the Sir Joseph Banks Grp. Proc. R. Suc. Viet. 30, 2), 312-526. Rracheurx, M., 1942. A systematic list of the HMydroida of South Australia with a suninary of their distribution in other seas, Trans. R, Soc, S. Aust. 6B (1), 104-118. Coxoven, J. T. with Simepunvu, J. MeN., 1964. Effect of Sareassuin distribution on its eptbiota and antibacterial activity. Botanica mar. 6, 147-157. HabeaGs. ne 1950, A revision of the ‘Tasmanian [yrlrida. Pap. & Proce. R. Soc. Tasmatsia, 1949, 1-65, kKaio, M. Nakanuna. K,. Tlar, E., and Kaxouma, Y,, 196). The distribution pattern of hydvozoa on sen weeds with some notes on the so-called coaction among hydrozoan species, Bull. soar, Biol. Stat. Asanvwshi 10, 195-202, Mutogn, J. F., and Tresiicock, 2. E., L911. Notes on Victorian bydroida with descriptions of new species, Geelong Nat. (2) 4. (4), 115-124. MeTacuisn, f., aid Cnarom, J. $., 1964. Algal inhibition hy yellow iltraviolet-absorbing substances from Faeus vesiculosus. Cauad, |. Bot. 42, 287-292. Nestsiurs. M., 1965. The association between Hydrozoa and their attachment substrata with special reference to algal substrata, Bull, mar. Biol. Stat. Asamushi 12, 75-92. Nrswraima, M., 1968, Ecological distribution of epiphytic Hydrozoa an the Tsuchtyx Gost tear the Marine Bioloygieal Station of Asamushi. Ibid, 12, 179-205. Nisnuira, M., 1967a. Observations on the ulwal selection by the larvae of Sertularella miuren- ats in nature, Ibid. 13, 35-48. 146 S, A. SHEPHERD anp J. E. WATSON Nera, M., 1967b. Dispersal of the larvae of a hydroid Sertularella miurensis. lbid. 13, Nisomima, M., 1968a, Experiments on the algal selection by the larvae of Coryne uchidai Stechow (Hydrozoa). Ibid. 18, 83-89. Nisuauma, M., 1968b. Brief experiments on the effect of algal extracts in promoting the settle- ment of the larvae of Coryne uchidai (Stechow) (Ilydrozoa) Ibid. 13, 91-101, Oarino, C,, 1962. Tannins and vacuolar pigitents; in Physiology and Biochemistry of Algae. Ed., Lewin, R. A., 487 (Academic Press, N-Y-). Pennycuick, Pamea, R., 1959, Faunistic records from Queensland. V, Marine and brackish water hydroids, Pap, Dep. Zool, Univ. Qd. 141-210. Pl. 1-6. Ratru, Patricia M., 1956, Variations in Obelia geniculata (Linnaeus 1758) and Silicularia Besbinta (Conghtrey 1875) (Hydroids, F. Campanulariidae) Trans. R, Soc. N.Z. 84, 279- Rosins, M. W., 1969, The Marine flora and fauna of the Isles of Scilly, Cnidaria and Cteno- phora. J, Nat. Hist. 3, 329-3438, Rocicx, M, D., and Croaspace, H., 1949, Studies on Marine Bryozoa. IIT Woods Hole region. Bryozoa associated with algae. Biol. Bull. mar. biol. Lab., Woods Hole 96, 32-69. REARS J; = 1962. The association between Polyzoa and algal substrata. J. Anim, Ecol, 31, 331-338. Suervern, S. A., and Womenrstey. H. B. §., 1970. The sublittoral ecology of West Island, ier italy, I Environmental features and the algal ecology. Trans. R. Soc. S. Aust. 94, 105-138. Srenurtn, J. MoN., and Conover, J. T., 1965. Sargassum Tannin, an antibiotic which retards fouling. Nature 208, 52-3. Stoane, J. F., BAssINDALE, R., Davenport, E. W., Epurve, F. J., and Krraune, J. A., 1961. The ecology of Lough Ine IX, The fauna and fora associated with undergrowth-forming algae in the rapids area, J. Ecol. 49, 353-368. Srecnow, E., 1924. [. Wissenschaftliche Mitteilungen, 1. Diagnosen neuer Hydroiden aus Australien. Zool. Anz. Leipzig, nix, 57-72, Titomeson, D’A. W., 1879. On some new and rare Hydroid Zoophytes (Sertulariidae and Thuiariidae) from Australia and New Zealand. Ann. Mag. Nat. Hist. (5) 3, 97-114, Watson, Jeanetre E,, 1969. Scoresbia a new hydroid genus from South Australian waters. Trans. R. Soc. S. Aust. 93, 111-116, Plate. Womens.ey, H. B. S., 1967. A critical survey of the Marine Algae of Southern Australia, II Phaeophyta, Aust. J. Bot. 15, 189-270. A NEW GENUS OF TREMATODE (DIGENEA; GORGODERIDAE) FROM THE URETER OF TUNA FISH (THUNNUS THYNNUS MACCOYID) IN AUSTRALIA* BY HAROLD W. MANTER{ Summary A large, digenetic trematode is described from the ureter of the tuna Thunnus thynnus maccoyii from southern Australian waters. It represents a new genus and species, Cefiotrema crassum (subfam. Gorgoderinae) distinguished by the size and shape of the body, the caeca being distant from the sides of the body, the uterus being inter-caecal, the vitellaria arising as three claviform lobes on each side and the seminal vesicle at least partly anterior to the genital pore. The genus is close to Phyllodistomum Braun; P. carangi Manter, 1947, is considered to belong to Cetiotrema; P. lancea Mamaev, 1968 is very similar to Cetiotrema crassum in some features but, largely on account of the form of the vitellaria, is retained in Phyllodistomum. A NEW GENUS OF 'TREMATODE (DIGENEA; GORGODERIDAE) FROM THE URETER OF TUNA FISH (THUNNUS THYNNUS MACCOYIL) IN AUSTRALIA* by Harourp W. Manrert SUMMARY A large, digenctic trematode is described from the ureter of the tuna Thunnus thynnus maccoyii trom southern Australian waters. It represents a vew genus and species. Cetiofrema crassum (subfam. Gorgoderinae} distinguished y the size and shape of the body, the caueca being distant from the sides of the body, the uterus being inter-caecal, the vitellaria arising as three claviform lobes on each side and the seminal vesicle at least partly anterior to the genital pore. The genus is close to Phyllodistemum Bruun; P, carangi Manter, 1947, is apndidered to belong to Cetiotrema; P. laicea Mamaev, 1968 is very similar to Cetiotremu crassum im some features but, largély on account of the form of the vitellaria, is retainéd in Phyllodistomum. The trematodes described below were sent to me by L. Madeline Angel, of the University of Adelaide, South Australia, They were collected hy the Common- wealth Scientific & Industrial Research Organization (C.S.1,R.0.) from East Bass Strait and Kangaroo Island in 1939, Two specimens were collected from cach of twa tuna fish, The three complete and one incomplete specimens are remarkable for their large size, To the naked eye they suggested in size and shape such trema- iodes as Fasciolopsis buski but were even more muscular. Each specimen was sharply bent ventrally near midbody and evidently strongly contracted. [t was necessary to unfold (or cut) and then compress the specimens before they could be mountcd on a slide and studied. After staining in Delafield’s haematoxylin, each specimen was clamped between two slides, using brass clamps with screws to compress the slides tightly together, then passed through the alcohols to 100% before releasing. Compression of living specimens at the time of killing is. preferred handling, but no important distortion scems to result from coheierable mechanical pressure after preservation. However, only limited flattening can be achieved in this way. The large size of these worms indicates they must bend or curl within the ureter of their host and their mass is such that some injury to the tuna must result. No information on incidence or intensity of infection is available. Most parasites of such large size, especially when infecting a host of economic importance, are described in early literature. The location in the urcter, an organ often not examimed for parasites, may explain why this genus seems to be undescribed. FAMILY GORGODERIDAE Cetiotrema crassum gen. nov., sp. nov. (Figures 1-3) Host: Thunnus thynnus maccoyii (Castelnau); Thunnidae; southern bluefin tuna. Localities; East Bass Strait and Kangaroo Island, South Australia. Collected by: C.S.I.R.0.; 1939. Number: 4 (one incomplete); 2 from 1 host in each locality. * Stadivs from Dept. of Zoology No, 419, 1 University of Nebraska, Lincoln, Nebraska, USA Trans, R. Soc. S. Aust. (1970), Vol. 94, L48 H. MANTER Holotype: South Australian Museum, No. E863. Paratype: U.S, National Museum, Helminth. Coll, No. 71424. Description (Measurements on 3 specimens, all somewhat contracted and eoriiwesice after preservation. Measurements are in mm unless otherwise indt- cated): Body very large, thick, muscular, with almost parallel sides, broadly rounded at each end. Length 20-0 ta 25-5; width 7:5 lo 5-5. Sides of body thin and slightly thrown into short folds, Dorsal surface smooth; ventral surface, Where not eroded, covered with minute papillae. Strong longitudinal muscles in pitrenchyma except near sides of body. Oral sucker yentral, snbterminal, circular, 1-2 to 1-5 wide. Farebody 2-755 to 3:8 long, Acetabulum circular, with civeular aperture und longitudinal cavity; 1/235 to 1:615 wide. Sucker ratia 1:1. Pharynx lacking, bul anterior portion of oesophagus thick-walled, Oesophagus (contracted) about 0-348 to 0-536 long; bifurcation slightly nearer oral sucker than to acetabulum, Caeea extending ta within 2-185 to 2°7 of posteriur end of beady, not far apart; dividing body width into approximate thirds, Genital pore median, about midway between acetabulum and bifurcation of vesophagus. Testes a little anterior to midbody, avnid, smooth ar slightly crenu- lated. diagonal, intercaecal, separated by short space; 1-52 to 2-28 long by 1:14 ta 2-09 wide. Semitial vesicle a rounded to elongate sac, inconspicuous, belween aeclabulum anid bifurcation of oesophagus, partly anterior to genitul pore; cirrus sac and cirrus absent; prostatic duct short, surrounded by small, radially arranged prostatic cells, antero-clorsal to genital pore. Ovary ovoid, smooth, to right of midline, pretesticular, separated from anterior lestis by uterine coils. Vitellaria immediately anterior and to left of ovary, inter- caecal; consisting of claviform lobes, three on each side, sometimes branchine. Seminal receptacle lacking. Uterine coils narrow, extending to ends of eaeca or slightly beyond; mostly intercaccal but frequently slightly lateral to cacca ven- trally; extending between testes, between anterior testis and ovary, and Jateral to acetabulum on both sides. Metraterm glandular er at beast lined with cells, longitudinal, between genital pore and acetahulum. Eges 38 to 45 by 20 ta 29 microns; operculum apparently lacking; embryo only partially developed. Excretory pore conspicuous, dorsal, glandular, 1-140 {0 1-158 auterior to posterior end of body. Excretory vesicle not secn, Diseussion: Distinctive characters of Ceflotrema are large body size; broadly raunded ends; thick body but with thin sides; caeca distant from sides of budy which are largely unuccupied by organs; chicfly intercaecal uterus: vitelbaria consisting of claviforrn lobes arising as three on euch side; and seminal vesicle ak ie purtly anterior to genital pore. Other Gorgaderinac are generally much smaller, The genus Phyllodistomum Braun, 1899 conteins many species occurring in the urinary blader of both marine and freshwater fishes. These species. are thin- badied and usually have a length of one to a few millimeters, 1t is, however, the nearest related genus to Cefiotrema, and one species, P. carangis Manter, 1947 {Fig. 4). 6mm in length, from Caranx ruber (Bloch) in the Gulf of Mexico, can he considered a second species of Celiotrema. It differs from C. crassum in smaller size and other characters. but agrees in broadly rounded ends; caeca distant from sides of hody; vitellaria consisting: of three clangate Jobes; papillae on the ventral surface; narrow, intercaecal uterine coils, and seminal vesicle anterior to the genital pore, It is from a pelagic fish, Although found in the hady cavity, it probably was from the urinary bladder, Phyllodistomum caranzis was compared with P. acceptum Looss, 1901, from the urinary blader of Crenilabrus spp. in the Mediterranean. Phyllodistomum acceptum does seem to have somewhat similar A NEW GENUS OF TREMATODE 149 vt 55 Figs. 1-3. Cetiotrema crassum. Wig. 1: Holotype. Ventral view. Fig. 2: Vitellaria of a paratype, Ventral view. Fig. 8: Terminal genital ducts. Ventral view. Fig. 4: Cetriotrema carangis (Manter, 1947), Dorsal view. (From Manter, 1947), All figures were drawn with the aid of a camera lucida. The scale is in mm. Abbreviations: ep, excretory pore; gp, genital pore; mf, metraterm; ov, ovary; sv, seimnal vesicle; ¢, testis; ut, uterus; vt, vitellaria, vitellaria but the body is more tapered, the caeca nearer the sides of the body, the seminal vesicle posterior ta the genital pore, and the uterine coils extend nearly ta the sides of the body, Considering these characters together with the host, P. acceptum seems to be closely related to P. (Vitekkarinus) crenilabri Dolgikh & Naidjenoya, 1968 from the Black Sea. 15} It. MANTER Mamaev (1968) has described a species, Phyllodistomum lancea, from the kidney of Euthynnus affinis and Auxis thaazard in the South China Sea, It is related to C. crassum and perhaps should be considered a third species of Cetio- trema. \t does not appear to have a wide body with rounded ends but its figure shows longitudinal lines suggesting that the sides of the body may be folded inward ventrally. Its seminal vesicle is entirely anterior to the genital pore. How- ever, the yitellaria are rather compact, lobed, grape-like masses rather thun elongate tubes, and chiefly on that basis the species is retained for the present in the genus Phylodistomum. It is about the same size as C. carangis. Generic Diagnosis of Cetiotrema: Gorgoderidac. Gorgoderinae. Body large, with almost parallel sides and rounded ends; sides of body thin but rest of body may be highly muscular. Minute papillae ou ventral surface. Suckers equal or sub- equal in size. Testes ovoid, diagonal, intercaecal; cirrus and cirrus sac lacking; seminal vesicle at least partly anterior to genital pore. Ovary pretesticular, to right of midline; seminal receptacle lacking. Vitellaria of three claviform lobes on cach side, sometimes branching at ends; preovarian. Uterus of narrow coils, mostly or entirely intercaecal. Eggs non-opcrculate; embryos partly developed. Exeretory pore dorsal, well anterior to posterior end of body. Parasitic in the urinary bladder or ureters of pelagic marine fishes. T'ype species: Cetiotrema crassum, Other species; Cetiotrema carangis (Manter, 1947) nu. comb. The name Cetioirema is from cetio = monstrous or large; and trema, for trematode. The name crassum is from crassus = thick, referring to the thick, muscular body of that sptcies. Known lite cycles ot Gorgoderidae are as yet limited to freshwater species, but those of marine species are probably similar. The molluscan host is a bivalve molluse; cystocercous cercariae develop in daughter sporocysts, emerge, and are ingested by a second intermediate host which, in different species, may be a variety of animals: insect larvae, crustaceans, snails, or tadpoles. In one species, Phyllodistomum simile Nybelin, 1926, precocious metacercariac in sporocysts are infective to the final host. Life cycles of marine species probably involve bivalve molluscs and Crustacea. REFERENCES Manter, Haroip W., 1947. The digenetic trematodes of miarine fishes of Tortugas, Florida. Amer. Mid. Nat... 88 (2), 257-416. Mamaev, Iv. L., 1968. Helminths of tunny in the South China Sea. In (pp, 5-27): Skrjahiu, K. f. & Mamaey, I. L. Helminth Animals of the Pacific Ocean. (in Russian.) Moscow. 1968. THE CAINOZOIC STRATIGRAPHY OF THE EASTERN COASTAL AREA OF YORKE PENINSULA, SOUTH AUSTRALIA BY WILLIAM J. STUART, JNR.’ Summary The Cainozoic succession occurring in coastal cliffs along the east coast of Yorke Peninsula consists of paralic sediments. The Muloowurtie Formation and a partly-included sand tongue, newly described and named Quartoo Sand Member, make up the lower part of the "Muloowurtie Clays". The upper part is re-described and named the Throoka Silts. The Port Julia Greensand, in an expanded sense, is regarded as a member of the Rogue Formation (new name). The overlying Port Vincent Limestone is described and named. The first phase of Cainozoic accumulation commenced with the deposition of Middle to Upper Eocene fluviatile sediments, During early Upper Eocene to Miocene time, sediment accumulation was mainly marine except for a thin interval of sediments, which indicates lagoonal deposition. Marine deposition took place during the Upper Pliocene, and during the Quaternary fluviatile deposition was dominant over marine accumulation in the coastal area. Earth movements occurred during the Cainozoic Era along ancient fault lines in Cambrian and basement rocks. These movements, which either faulted, folded or tilted Cainozoic beds took place during early Upper Eocene, Oligocene. Middle Miocene to Lower Pliocene and the Quaternary. Facies relationships and the distribution of Tertiary sediments suggest that linear elements played an important role during the accumulation of these sediments, as boundaries between either areas of variable subsidence or areas of relative stability and subsidence. In general, Yorke Peninsula can be subdivided into blocks, which at times during the Tertiary were undergoing reasonably uniform movement, but at other times the blocks moved independently of one another. THE CAINOZOIC STRATIGRAPHY OF THE EASTERN COASTAL AREA OF YORKE PENINSULA, SOUTH AUSTRALIA by William J. Stuart, Jnr. SUMMARY ‘The Cainozoic snecession ocewsring in coastal cliffs along the east coast of Yorke Peninsula consisty of paralic sediments. The Muloowurtie Formation and a partly-inclided sand tongue, newly described and named Quarton Sand Member, make wp the lower part of the “Muloowurtie Clays”. ‘The upper purt is te-deserjbed and named the Throoks Silts. The Port Julia Greensand, in an expanded sense, is regarded us a member of the Roguc Formation (new name), The overlying Port Vincent Limestone is: described and named. The first phase of Cainozoie accumulation commenced with the deposition of Middle to Upper Eucene fuviatile sediments, During early Upper Eocene to Miocene time, sedi- ment accumulation was mainly marine exeept for a thin interval of sediments which indivates layoonul deposition, Marine deposition took place during the Upper Pliocene, und during the Quaternary fhiyiatile deposition was dominant over marine accumulation in the coastal aren, Earth movements occurred civing the Cainozaie Era along ancient fault lines in Cambrian aud basement rocks, These movements which cither faultect, fulded or tilted Cainozoic beds tonk place during early Upper Eucene, Oligocene. Middle Miocene to Lower Pliocene and the Quitemary, Pacies relationships and the distribution of Tertiary sediments suggest that linear elements played an important role during the accumulation of these sediments, 4s boundaries between either areas of variable subsidence or areas of relative stability and. subsidence, In general. Yorke Peninsula can he subdivided into blocks which at times during the Tertiary were undergying reasonably nniform movement, but at other times the blocks snoved independently of one another. INTRODUCTION General Statement In South Australia, good exposures of Tertiary sedimients occur in coastal cliffs along the east coast of Yorke Peninsula. This area is situated on the western margin of the St, Vincent Basin (Fig. 1) where paralic accumulation prevailed during the Cainozoic Era (Glaessner and Wade, 1958). Although much work has been undertaken on the stratigraphic relationships of Tertiary strata in the eastern side of the basin, there has been no comprehensive study of these secli- meats in its western side. A clear analysis of the geological history of the St. Vincent Basin recnires discrimimative naming of rock stratigraphic units which form an essential frame- work of reference, but formal nomenclature for sediments along the east caast of Yorke Peninsula is unavailable in the litorature except for the Muloowurtie Clays of Tepper (1879) and the Port Julia Greensand of Crawford (1965), In recent years, the Tertiary sediments have been discussed as time-straligraphie eqniva- lents of the formally-named Tertiary sediments on the castern side of the St. Vincent Gulf, but distinct rock units and complex facies variations over short distances warrant introduction of a new stratigraphic nomenclature. Only the Terliary succession is.discussed in detail in this paper, but the general Quaternary succession, as exposed in coastal cliffs, is also inchided for completencss of coastal sequences, The purpose of this paper is not only to provide a time and rock unit framework, but lo decipher the geological history in this area and the role of relative earth movements taking place during the Cuinozoic Era. 1 Geosurvevs of Australia Pty. Ltd., Adeliide, S.A. Trans. KR. Soc. S. Aust. (1970), Vol, 94, 152 WILLIAM J. STUART Procedures The coastal profiles (Figs. 2, 3, 4) were constructed by sketching coastal cliffs, the heights and distances controlled by topographic base maps and measured stratigraphic columns, The profiles are idealized in the sense that in several places either scree or grasses obscure the sediments. However, where the tracing of beds was difficult, columns were described and measured after the debris was removed by trenching. LEGEND | LOCATION OF COASTAL PROFILES ciintn FAULTS: Pricey . SYNCLINES 3 FAUL] BLOCKS / Ardrossan SCALE MILES © 4 8 12 1 KILOMETRES | ’ ] Muloowurtie A } Point PENINSULA J BLACK POINT Black Poigy’ P WELL N°! & Wy , C 7 R 7 7 Y 7 Port Vincent 5 Edithburgh a gl ROUBRIDGE WELL, N° Troubridge Shoal STRAIT investiGATor |, Map ‘showing the location of coastal profiles, faults, synclines, and parts of fault blocks STRATIGRAPHY IN YOURE PENINSULA 153 Several samples of Tertiary sediment wete examined fur foraminifera which were used for the purpose of correlation. Locations of these samples are not shown in this paper, but are on file at the Department of Geology, University of Adelaide. STRATIGRAPHY General Statement The Cainozoic succession exposed in coastal cliffs along the east coast of Yorke Peninsula consists of alternating marine and non-marine sediments, Coastal profiles of these sediments are presented in this paper from immediately south of Rogue Point to § Kilometres south of Port Vincent (Figs. 2, 3, 4). The sue- cessian is, in ascending order, comprised of a basal fluviatile scdiment unit (am-named), marine Muloowurtic Formation (redefined), lagoonal Thruoka Silts (new name); marine Rogue Formation (new naine), marine Port Vincent Limestone (new name), marine Hallett Cove Sandstone and ?Pleistocene fluviatile and subrecent marine sediments (un-named), In the discussion of these fonnations it is conyenient to subdiyide the coastal area into a northern portion between Rogue Point and Black Point and.a southern area between Black Paint and Edithburgh. The formations of Tertiary age are correlated with sediments of this age which were encountered in the Black Point No. 1 Well, Troubridge No. 1 Well and exposures at other localities on Yorke Peninsula. The discussion begins wilh the basal Middle ta Upper Eocene fluviatile sediments. BASAL. FLUVIATILE SEDIMENTS Distribution and lithology Tnland in the vicinity of Ardrossan aud Price Townships, Middle-Upper Eocene quartz sands and sandstones with subordinate conglomerates, siltstones and clays are found in isulated outcrops and quarries (Crawford, 1965). These sediments are preserved in hollows within the basement and vary in thickness with a maximum of 11 metres at Correll’s sand quarry, A small remnant of iuyiatile conglomerate is present immediately south of section 9 (Fig. 2), Sancls and conglomerates, 16 metres thick, are found below 155 metres in the Black Point Well, South of Black Point along the east coast of Yorke Peninsula and at lower levels in the Troubridge well, Huviatile sediments of Middle to Upper Eocene age are absent, Quarlz comprises ut least 95% of the Auviatile sands, but mica and feldspar wre common acccssory minerals. Within conglomerates, pebbles are essentially resistant rock-types: quartz, quartzite and vein quartz with subordinate arkosic sandstone. The clay mineralogy of samples from lenticular clays is predominantly kaolinitic with traces of illite and montmorillonite, The exposed flayiatile sediments are laminated to thinly bedded. They contain small to medium scale cross-stratifications (planar and trough; in the sense of Mckee and Weir, 1953). Coarse channel-lag deposits are common over an irregulur basement surface which has approximately 5 metres relief in the B.H.P, quarry. Palacocurrent analysis of cross-strata was attempted to establish the dominant directions of stream transport of Middle to Upper Eocene sands. It is apparent that only two locations are suitable tor direct measurement of current directions in the northern portion of Yorke Peninsula (Fig. 5), su that conclusions can anly be tentative, Channel and cross-strata directions in the B.H-P. quarry and Crowell’s sand quarry near Ardrossan indicate transport to the east-southeast (Pig. 5). This suggests stream transport towards the present axis of the St. Vincent Gulf, ‘The next phase of sediment accumulation is recorded by Ue marine Muloowrtie Formation. 154 WILLIAM J. STUART Cross—stratification directions measured from (A) Crowell's sand quarry and (B) B.H.P. quarry. Arrows indicate mean direction of cross — stratifications. One radius equals 55 measured cross —stratifications. MULOOWURTIE FORMATION Definition Tepper (1879) applied the name “Muloowurtie Clays” to a_ marine sequence between Rogue and Muloowurtie Points of (in ascending order) fossiliferous, ochre-yellow clay with oysters, echinoderms, pelecypods and fish teeth; white plastic clay; one inch of arenaccous limestone with Fibularia gregata Tate; 3 to 6 metres of unfossiliferous ochreous clays. The “Muloowurtie Clays” actually con- sist of biogenic calcarenites, quartz sands, calcareous and glauconitic quartz sands and sandstones and minor thin conglomerates, sills and clays. Because the “Muloowurtie Clays” contain several non-clayey rock-types, the name Muloo- wurtic Formation is preferable, As used here, it is restricted to sediments below the “unfossiliferous, ochreous clays”, The “unfossiliferous ochrcous clays” are assigned to the lagoonal Throoka Silts which disconformably overlie the Muloo- wurtie Formation. Type Section The type section of the Muloowurtie Formation is located at Sliding Rocks {Sach 3, Fig. 2), The formation as restricted is about 12 metres thick and uncon- ormably overlies the Lower Cambrian Kulpara Limestone (or Ardrossan Marble of Tepper). Green glauconitic quartz sands containing thin lenses of pebbles are found in the lower 2 metres of the formation. Subround to subangular pebbles of quartz, quartzite, limestone and arkosic sandstone within the sands were probably derived from local source areas of pre-existing Tertiary sediments and Cambrian rocks. The sands are moderately-sorted and medium- to coarse-grained, Glau- conite in the form of pellets id internal moulds of foraminifera rarcly exceeds STRATIGRAPHY IN YORKE PENINSULA 155 10% of the bulk composition. The glaueonitic sands were not recorded by Tepper, but are here included in the definition of the Muloowurtic Formation. Richly fossiliferous sands containing a few quartz, pebbles gradationally overlie the glauconitic sands. The following fossils were recognized: the echinoids Fibularia gregata Tate, Salenia tertiara Tate, Evpategus, crinoid plates, brachio- ods, lamellibranchs, the bryozoans Retepora and Cellepara, ostracods and Motanifoifers The fossiliferous sands yertically grade to calcareous, silty Lo fine, quartz sands. The quartz sands decrease as carbonate constituents increase upwards and they grade to silty, biogenic calcarenites. The carbonate constituents consist of numerous foraminifera, smull shells and fragments, and common echinoid spines. The clay and silt fraction of the carbonates varies between 10 und 20 per cent. The sediments contain lenticular laminae and very thin beds. Ripple-marks and burrows occasionally occur within the sequence. These sedi- ments are the fossiliferous, ochre-ycllow clay and white plastic clay of ‘Tepper. They are about 5 metres thick and often are speckled buff by iran-oxide staining, The calearenites in tum vertically grade to yellowish grey, calcarcous, very fine to medium quartz sands often argillaceous and silty, They are overlain by resistant, calcareous, very fine to fine quartz sandstones which are very finely- bedded to thin-bedded. The sandstones contain an interbed of pale nish grey and buff silt. The upper 91 centimetres of the formation cumsists of variegated, argillaceous, quartz sands interbedded with arenaceous clays, The sediments above the calearenites probably constitute the arenaceous, yellow clay aud sand- rock of Tepper, They are about 4 metres thick. Distribution and lithology For about 800 metres north of Sliding Rocks only minor facies variations are found within the Muloowurtic Formation as it gradually dips below sea level (Fig. 2), At Sliding Rocks basal glauconitic sands overlain in part by finely bedded calcareous sands both thin ta a depositional edge on the Cambrian Kulpara Limestone, Immediately south of Sliding Rocks, a second glauconitic quartz sand is found near the middle of the Muloowurtie Formation. [t increases in thickness to the south (Sect. 4, Fig. 2) and forms an extension of the Quartoo Sand, new name, a Member of the Muloowurtie Formation (p, 160), The sand tongue divides the remainder of the Muloowurtie Formation into lower beds A and uppey beds Pe Seema units) which can be recognized at section 3 and further north Pig, 2), The Muloowurtie Formation dips below sea level on the north side of Muloowurtie Point but reappears to the south in coastal cliffs and is traced almost ta Section 6 where calcareous sands and arenuceous calearenites of the lower beds thin to a depositional edge on Precambrian crystalline basement (Fig, 2 just north of Section 6), Because the topography of Lament is irregular, they exhibit minor facies changes in the vicinity of a hollow located at sections 6 and 7. Ata lower level in the hollow (Sect. 7) glanconitic und richly fossiliferous quartz sands are overlain by calcareous sands and arenaccous calcarenites, They show vertical grain size trends similar to those in the sequence at the type section. At slightly higher levels on the hollow (Sect. 6) a thin sandstone with small ta lange pebbles of quartz, quartzite and granite gneiss contains occasional brachio- pods, and numerous oysters. On nearby basement an oyster was found in growth position. The fossiliferous sandstone is separited from glauconitic and richly ossiliferous sands by calcareous sands and arenuceous calcarenites filling in the hollow, This suggests that the basal glauconitic and richly fossiliferous sands and the fossiliferous sandstone were probably deposited at about the same time on 158 WILLIAM J. STUART submarine, low dipping surfaces located at different levels, Oysters Hourished in a higher energy environment on the higher surface. In the vicinity of Tarts Mine, the thickness of the lower beds is about 3 metres. A basal povrly fossiliferous transgressive conglomerate with quarty, quartzite and granite gneiss pebbles overlies Precambrian basement (Sect. 8, Fiy. 2). On the wave-cut platform, it overlies Cambrian arkoses and coritains numerous fossils, At section 8, vellowish grey moderately- to poorly-sorted fine and ynedium quartz sands with occasional fossils overlie the basal conglomerate. They are overlain by 30 centimetres of resistant, grey-white, very calcareous, vourse la very coarse, quartz sandstone with granules, The basal transgressive conglomerate is stratigraphically controlled by an overall rise of basement beginning ahout 92 metres south of Harts Mine (Fig. 2). This partly explains the thinning of the overlying quartz sands to less than 1 metre in a southerly direction. The sands also thin by lateral gradation to coarser sands of the Quartoo Sand Member. The boundary between the lower beds and the Quartoo Sauds is arbitrarily drawn on Fig. 2. At Rocky Point about 4 metres of laminated and thin-bedded valcarcous sands and biogenic calearcnites overlie a thin basal conglomerate (Sect. 13, Fig, 3). They show vertical grain size trends similar to lower beds A in northern areas. About 1 kilometre south of Rocky Point they dip below sea level. To the north the sediments mostly thin to a depositional edge on Cambrian arkoses and conglomerates. The upper few feet laterally grade to coarse sands and con- clomerates, and again the boundary of this part of the Muloownrtie Mormation and the Quartoo Sands is arbitrarily drawn on Fig, 2, The depositional thinning ut the lower parts of the formation north of Rocky Point and south of Harts Mine accompanied with an increase in quartz constituents and proportionate decrease in carbonate show a depositional high between these two: areas. Considering upper beds B. south from sections 3 to 6: very fine calcareous quartz sandstones and sands laterally grade to lenticular sands, arenaceous calcarenites and arenaceous silty clays (Fig. 2). In general, these sediments become coarser grained to the south. At section 8, thin beds of greenish grey sitrds are interbedded with these sediments. They arc considered thin extensions of the Quartoo Sands. Although clay minerals are subordinate to quartz and carbonate constituents in the Muloowurtie Formation, montmorillonite aid glauconite are common with variable amounts of halloysite and traces of chlorite and illite. Traces of the zeulite clinoptilolite are also present within the formation. QUARTOO SAND MEMBER OF THE MULOOWURTIE FORMATION Definition The nam Quazloo Sand Member is applied to variegated pale to dark green, buff, pale grey and red, quartz sands which conslitule the upper half of the Muloawurtic Formation in the vicinity of Pine and Rocky Points (Pig, 2), The type section (13) is located ut Quartov Point (now called Recky Point). Here, 3 metres of quartz sands grade from very fine sands at the base to coarse and very coarse sands with granules near the top of the sequerice. They are fairly well-sorted with a deficiency in clay and silt grades. Bands of guethite staining ge vommon near its base and red iron oxides occur at upper levels, Distribution and lithology _ From its type section the Quartoo Sand Member extends northwards to the Vivinity of section 9 and gradually beeonies coarser grained (Fig. 2). Medinm STRATIGRAPHY IN YORKE PENINSULA 157 to very course quartz sands with granules and ocvasional pebbles are pre- dominant, The sands are thin- to thick-bedded in contrast to finer bedding in other parts of the Muloowurtie Formation, The Quartoo S:ands first overlie yellowish grey calcareous sands in the lower part of the Muloowurtie Formation with gradational contact, then to the north extend onto basement rocks near section 12, Between sections 9 and 10 the thickness of the member is mostly controlled by erosional irregularities of basement. A maxiraum thickness of 4 metres ts found at section 12, Patches of thin basal conglomerates either are contined to small erosional hollows or lie on low dipping erosional surfaces. Although erosion has removed the Quartoo Sand Member between section 9 and 10, pale grey and green calcareous fine to coarse quartz sands with granules mostly intertongue and laterally grade to other parts of the Muloowurtie Formation in the vicinity of Harts Mine aud further north towards Sliding Rocks (Fig. 2). From immediately south of Harts Mine through Rocky Point the absence of upper leds B could be explained by erosion prior to. the deposition of the Throoka Silts, but thin green quartz sands interbedded with the upper beds in the Tarts Mine area suggest that the main reason for their absence further south is lateral gradation to the Quarteo Sands, From Harts Mine through section 3 at Sliding Rocks, a poorly fossilifercus greenish grey quartzose sand extension of the Quartoo Sands, 30 centimetres thick, constitutes the uppermost bed of the Muloowurtie Formation (Fig, 2). At upward increase in grain size is a characteristic textural feature of the Quartoo Sands and its lateral extensions, They are considered regressive, marine sands, Patches of thin conglomerates overlving basement between sections § and 10 on the depositional high show the only departure from the coarsening upwards trend, Here quarlz sands fine upwards for a few metres above the conglomerates then show the coarsening upwards trend. The conglomerates were probably depasiled during the initial ingression of the Upper Eocene sea. Regression is further substantiated between Harts Mine and Sliding Rocks by the stratigraphic distribution of the glanconitic sand longue separating lower beds A and upper beds B. To the north it becomes moderatc- to poorly-sorted with a general decrease in grain size, greener m colour with an increase in glauconite, and more fossilitcrous with Fibularia gregate. echenoid spines, lamellibranch fragments and foraminifera. The sands of this tongue nally grade northwards tu buff speckled yellowish grey, calcarcous, fine, quartz sands near the top of the lower beds. This relationship can be scen just south of Sliding Rocks where large sigmoidal ripples are found within a thin gradational unit separating the lower beds and the glauconitic sand tongue. The vertica] gradation of biogenic calearenitus to calcareous quartz sands near the top of the lower beds and its counterpart south of the depositiona] high also suggest regression. As shown by better sorting within the Quartoo Sands and the rare preservation of fossil fragments and glauconite pellets, they were deposited under higher energy conditions aver the pre-existing depositional high then extending south past Rocky Point. The deposition of upper beds RB north of the depositional high indicates a return to slightly lower cnergy conditions before the final regression near the top of the formation. THROOKA SILTS Definition and distribution The name Throoka Silts (from Throok Creek, Hd. of Mulonwurtie) is applied to a thin (2-3 to 3-6 mebres) sequence of silts and quartz sands which are the “unfossiliferaus ochreous clays” Tepper [{1879) recognised between 59 WILLIAM J, STUART Rogue and Muloowurtie Points, The type section is located at section 4 between Sliding Rocks and Muloowurtie Point (1"ig, 2), The formation is easily recognised by its pale colour streaked with thin bands of goethite iron-staining often purallel with bedding, and Liesegang rings. Except for minor gaps it is traceable in coastal cliffs between Rogue and Black Points. Disconturmities separate the lzgoonal Throoka Silts from the underlying Upper Eocene Muloowurtic. For- mation, and the anderlying marine, Rogue Formution, These surfaces indicate only small hiatuses, Litholougy At the type section (4) the Throoka Silts consist of laminated to very thinly bedded quartz sands and subordinate silty and arenaceous clays. No overall yertical or lateral textural trends are apparent. Musenvite is a common accessury miner! and kaolinite is the dominant clay mineral, There are also braces of illite and chlorite. Over the most southerly kilometre of outcrop, lenticular beds of laminated white and brown arenaceous clays are intercalated within very fine and medium quartz sands and silts. At Rocky Paint a 1 metre cross-stratified siliceous medium quirtz sandstone containing siliciied wood (Howchin, 1918; Glacssner and Wade, 1958, Crawford, 1965) underlies these sediments. Plant impressions are fannd on weathered ‘bedding planes. The sandstone contains numerous small seale, planar (with subordinate trough) cross-strata. Bedding cannot be traced through the sandstone to adjacent sunds and its shape forms a small lentil, This lentil of sandstave only occurs locally and Were is included within the Throoka Silts. Howchin (1918) noted “a similar sandstone located 1-2 kilometres nurth of Muloowurtie Point at a small headland”, The second siliceous sandstone is fonnd near the base of the overlying, marinc, Rogue Formation. The ‘Thravka Silts are not unfossiliferous as described by Tepper but contain large foramini- feral tests (Ammodiscus sp.) which are sacishtaals recognizable in oulerop. Other arenaceous foraminifera and rare Miliolids also are present. Inland and Subsurface Distribution of the Muloowcurtie Formation and Throoka Silts The Muloowurtie Formation and the overlying Throoka Silty van be seen for only a short distance inland along a few intermittent streams. A road-cut located 250 metres west of Muloowurtie Point contains the upper part of the Muloowurtie Formation, the Throoka Silts and part of the th Rogue Formation. The Muloowurtic Formation euusists of quart, sands that are similar to those of the giles Sand Member. About 0-8 to 1:6 kilometres inland between Muloowurtie oint and Ardrossan, remnants of the Rogue formation unconformably overtic basement on hill tops about 61 to 76 metres above sea Jevel. Although erosion has removed parts of the formations and no published subsurface data are avail- able, u section normal to the coastline would probably show facies relationships and depositional thinning similar to those within the Muloowurtie formation between Sliding, Rocks and the basement high south of Harts Mine (Fig. 2). The maxirnum known thickness of the Muloowurtie Formation is 70 metres in the Black Point well (Fig. 6). Here at 155 metres, the formation overlies fuviatile conglomerates mostly consisting of quartz granules. The basal 25 mvtres of the formation consists of pale grey and yellowish grey, moderately-sorted, medium and coarse, quartz sands with a thin 1-2 metre glauconitic quartz sand loczted - metres from the top of this sequence. The sands are poorly fossiliferous at Inwer levels with only occasional foraminifera, barnacles and shell fragments, STRATIGRAPITY IN YORKE PENINSULA 15y whereas near the top of this sequence foraminifera, echinoid plates and spines and Jamellibranch fragments are common. The basal sands are overlain by pale brown, biogenic valearenites with some interbeds of brownish grey. caleareotis clays and culcareous quartz sands. The calearenites contain cvarbonute con- stituents similar to those in the coastal sequence. Spunge spicules are reasonably common within the clays. Near the top of the formation the calearenites beeome arenaceous and are overlain by calcareous, moderately-sorted, medium, quartz sands, In the upper 3 metres of the formation well-sorted medium and coarse quartz sands occur at the same stratigraphic level as the regressive Quartoo Sands at Rocky Point. Between 76 and 79 metres a black lignitic sand and lignite over- lies the Muloowurtie Formation. It is about time-equivalent ty the Throoka Silts in the coastal sequence and was probably deposited in a marginal swamp. Although differential movements vonlemporancous with deposition account for some of the thickness variation in the Muloownrtic Formation between the coustal sequence and the lack Point well, the abnormal thickness of the for- tution in the well is here attributed mainly to a differential relict caused by faulting prior to the deposition of the Muloowurtic Formation, This is doeu- mented by murine sediments of (he Muloowurtie Formation separating the fluviatile sediments below 155 metres in the well frum an erosional remnant of fluviatile conglunerates located immediately south of section 9 [{ Fig, 3) and from those located about 61. metres above sea Jevel to the uerth towards Clinton. At least the lower 43 metres of the Muloowurtic Formation in the well is of lowermost Upper Eocene uge whercas the surface exposures also of Upper Eocene age are slightly younger (p. 173), The fuutting probably indicates a rejuvenation of movement along an asicicnt northeas!-southwest tuult zone located iu Cambrian and Precambrian rocks. Jn the Troubridge well the lower 49 metres of the Tertiary sequence consists of calearenites, clays and quartz sunds. On the basis of foraminifera, it is time equivalent ta the Muloowurtic Formation of Upper Eocene age in the Black Point well (Fig. 6). Permian basement in the Troubridge well is overlain by 30 metres of grey-white, fine ta medium, biogenic culearenites with ecasional zrey, caloarcous clays and a basal, yellowish groy, quartz sand. The calearenites contain bryozoal and shell fragments and foraminifera which are slightly re- crystallized. The calearenite sequetice is overlain by 12 metres of pale brown und grey, arenaceous, calcareous clays. The clays contain numerous glaucotite pellets and internal moulds of foraminiters at lower levels. Pale Irawn argilla- ceous fine biogenic calcarenites, 6 metres thick, overlie the clays. Both the clays and argillaceous calearenites contain well preserved foraminifera with occasional sponge spicules and Turritella aldingae, They constitute the lower part of a clay sequence, The description of rock-stratigraphic waits is hindered by. the absence of subsurface data from areas of pussible occurrence between Troubridge Shoal avid Black Point { Fig. 6), : Between 201 aud 210 metres in the Troubridge well, dark brown silty clays cuntain some lignitic fragments, vecasional foraminifera and glauconitic pellets, ‘they are dominantly marine bnt occur at about the same stratigraphic level as the Thragka Silts. Neither the Muloowurlie Formation nor the Throoka Silts are exposed in coastal clitts between Black Point and Edithburgh. For about 2-4 kilometres north of Port Vincent and in the subsailave further south, Lhe Rogne Formation uncon- turmably overlies Permian basemont. Although erosion by the second trans- gression that is documented by the luwer part of the Rugue Formation vould explain the absence of the Muloowurtie Formation and Throoka Silts in this urea, the sediments probably thinned ta a depositional cdge south of Black Point and 160) WILLIAM J, STUART seaward of the present coastline (Fig. 6). The absence of derived calcareous material such as lowermost Upper Focene foraminifera reworked into the Rogue Formation tends to suggest mainly depositional thinning, ROGUE FORMATION Definition The name Rogue Formation (from Rogue Point, Hd. of Muloowurtic) is applied to a mainly marine sequence consisting of quartz sands, sandstones and siliceous sandstones, siliceous and arenaceous limestones, mudstones and clays, Sands and sandstones are more common than other rock-types. Tepper (1879) called sediments between Rogue and Muloowurtie Points at lower levels in the formation the “Yurritella Grits”. Because the formation is characterized by numerous facies changes and crosion which limits its distribution, a composite type section is designated in coastal clits from Rogue Point to immediately south of Muloowurtie Point (Fig, 2), Distribution and lithology The Upper Eocene to Oligocene Rogue Formation is exposed at low tide at Ardrossan and extends intermittently in coastal cliffs from Rogue Point to 7-2 kilometres south of Port Vincen| (Figs, 2, 3, 4). It discontormably overlies the Threaka Silts in the northern area and unconformably overlies Permian basement immediately north of Part Vincent. About 1:6 kilometres west of the coastline and extending northwards from Throoka Creek to 2-4 kilometres northeast of Clinton, remnants of fossiliferous siliceous sandstones interbedded with sands averlie basement on low-lying hills (Tepper, 1879; Howchin, 1918; Crawford, 1965). Tepper (1879) and Howchin (19185 corrclated these rocks with siliccous santstones immediately south of Rogue Point which here are considered part of the Rogue Formation. At Muloowurtie Point, the Royue Formation is uncon- formably overlain by the Port Vincent Limestone. In the coastal clilfs south of Black Point, the two formations are conformable, Between Rogue and Muloowurtic Points, part of the Rogue lormation con- sists of cither thin-bedded, grey and grey-white, calcareous, siliceous quart. sandstones or arenaceous and argillaccous Jimestones with minor interbeds of brown and green arenaceous and silty clays, These rocks constitute a carbonate- siliceous facies, containing a fiuma of numerous Trrritella aldingae, sponge spicules and other fossils, Silica is disseminated in the sandstones and often forms layers and nodules, It has replaced carhonate in-some megafossils. Within a fow metres or less the rocks within the earbonute-siliceous facies laterally grade to grey-white and variegated slightly calcareous, quartz sands. The sands .are thin- to thick-bedded, They yary in grain size Jrom very fine- lo wedium-grained with occasional coarse beds. There is a decrease in grain size where the sands luterally grade to rocks in the carbonate-siliceotis facies. Thin beds rich in Turritellu can be traced from the carbonate-siliceous facies into the sands. In some places the sands have been leached of carbonate, but thin beds containing moulds of Turrifella are still traceable, The carbonate-siliceous lacies frequently forms headlands whereas the sand facies forms bays. Each occurs at various $tralgraphic levels in the formation. Immediately north and south of Muloowurtie Point the Rogue Formation forms part of a syneline plunging north of cast (Fig. 2). A fault on the north side of Muloowurtie Point accentuates the dips of the Rogue Formation, Throoka Silts arid the Muloowurtie Formation. The fault plane is essentially vertical trend- ing 10 degrees on the wave-cut platform. The displacement of the heds, which STBRATIGRAUHRY [IN YORKE PENINSULA ial are slightly downthrawn to the east js considered small, a few metres or less. To the south the fault strikes inland and is covered by soil and culctete. On the flanks of the syneline the composite thickness of the Rogue lormution is about dO metres. About 1] metres of the basal thin-bedded and massive, variegated, moderately-sorted, medium and coarse, quartz sands are exposed immediately north of Muloowurtie Point. The sands become calcareous and contain occasional arenaceous, glauconitie limestones towards Muloowurtie Point proper. They are overlain by 91 centimetres of dark green, glauconitic, quartz sand with occasional casts of lamellibranchs, bryozoans and corals. It is found near the top of voustal cliffs adjacent to the southeast corner of a smal] bay north of Muloowurtic Point and on the wave-eut platform at Muloowurtic Point. On the southern flank of the syncline pale quartz sands are found at the same stratigraphic level sugyest- ing i facies change ut depth near the axis of the syacline. The glauconitic sand is overlain by about 15 metres of pale grey and grey-white calcareous, very fine tu fine, quartz sandstones with some thin, hard limestones (Sect. 5. Fig. 2) The sandstones are thin- ta thick-bedded. In some beds, burrows are filled with glauconite while others contain siliceous nodules and sand-pipes. Only a few megatossils are found in these rocks, Near the axis of the syncline at Muloowurtie Point, soft yellowish grey, well- sorted, very fine to fine, quartz sands constitute the upper 4-5 metres of the Rogue Formation, They contain even and wavy, very thin bedding. faintly visible, small scale, cross-stratifications and oceasional symmetrical ripple-marks. Although the areal extent of the outerop is small, the sediments, sedimentary structures aera fossils siggest a beach environment and/or possibly backshore drifting sands. Between sections 5b and 6, stratigraphie relationships between the sand facies and carbenate-siliveous facies are similar to those north of Muloowurtic ¥oint in the Rogue Formation except that some sandstones have been cemented by secondary iron-oxides (Fig, 2), Between Harts Mince and Black Point, the lower part of the Rogue Formation consists of variegated grey, red and buff, medium to coarse, quartz sands ( Fig. 2), The carbonate-siliceous facies is absent in this area. The sands are very thin- to thinly bedded or often mussive. They contain thin lenses of small quartz and quartzite pebbles. AE luwer levels the bedding is either even or lenticular with oceasional ripples, At upper levels weathering has reorganized the sands and bedding features are obliterated. The bedding is not typical of a fluviatile enyiron- ment but could indicate a marine or leach environment. Oceasional moulds of Turritelia are found at lower Jevels in the formation immediately south of Rocky Point. They indicate marine influence although their lateral distribution is not great. A near shore, littoral to sublittoral environment is suggested for these sunds. Their distribution is similar to the Quartoo Sand Member of the Muloo- wurtie Formation. ‘They also indicate a higher energy environment than their fossiliferous counterparts to the north, sugyesting rejayenation of the depositional high from Harts Mine in the north to past Rocky Point in the south, Between Port Julia jetty and Port Vincent (Fig. 3), a composite thickness of the Rogue Formation ranges between 26 and 32 metres, The basal beds of the formation are only exposed for a distance of 2-4 kilometres north of Port Vincent, Here the lower 1] metres of the Formation consist of alternating calcareous quurtz sandstoncs and Iaminated silty clays. The clays contain numcrous Chlamys whereas the echinoid Duncaniaster is present in the sandstones. North of section 23 these beds dip helow sea level. 162 WILLIAM J. STUART The middle part of the Rogue Formation mostly consists of yellowish grey aud grey-white, moderately-sorted, fine ta medium, quartz sands and sandstones They are intermittently exposed in coastal cliffs between Port Vincent and Sheouk Flat, further north at the base of section 15 and south of Port Vincent between section 25 and 2 small creek south of section 26 (Figs. 3; 4). Over this distance the sunds and sandstones are ubout 6 to 8 metres thick. Immediately north of section 2) (Fig. 3) the uppermost sands laterally grade to calcareous siliceous sandstones which ire similar to those in the carbonate-siliceous facies located in the northern area, Between: Part Vincent and section 21 (Hig. 3), a resistant calvareous medium to coatse sandstone abruptly overlies the lower part of the Reguc Formation, Numerous low angle planar crass-stratifications within the sands are mostly oriented in a northerly directiow (Fig. 3). The sands are mustly massive but contain very thin to thin bedding and ueeasional ripples. The middle part of the formation is poorly fossiliferous except near the top and base of the seyuence where foraminifera become more common. Between Port Julia and Port Vincent, the upper part of the Rogue Formation consists mostly of interbedded, poorly-sorted, fine and medium quarty yands and sandstones with variahle amounts of carbonate and clay, Richly glauconitie sand- stones and mudstones, culeareous claystones, arenaceons limestones and silicenus sandstones are less common. Numerous facies changes take place over short distances and specific rock-types are shown in sections 14 to 24 (Figs. 3: 4). The upper part of the formation is more fossiliferous than the middle portion. Foraminifera, ostracods, lamellibranchs, gastropods, bryozoans, sponge spicules and sharks’ teeth are present. A resistant yellowish grey caleareous and siliceous sandstone 13 metres above the base of section 15 (Fig. 3) contains the gastropod Turritella tristira whereas beds below this sandstone contain Turritella aldingae. Varicgated poorly-sorted medium quartz sandstones with Chlamyy and other fossils oriented along the bedding gradationally overlie the middle part of the Rogue Formation. Most of the remaining rock-types in the upper part of the Rogue Formation display very thin to thick bedding. Drregularly lenticular bed- ding and burrows alse are present, At section 15 (Fig, 3). pale green slightly glauconitic quartz sands constitut- ing the uppermost beds of the Rogue Formation laterally grade to calearcous arenaceous claystones in the north and south flanks of a fold. The claystones are gradationally overlain by arenaceous, bryozoal calcareniles (Port Vincent Lime- stone). These can be traced southwards near beach level almost ta section 19. Here the Rogue Formation and Port Vincent Limestone have been uplifted along 3 high uugle reverse fault, The claystones in the Rogue Formation again laterally grade to mostly pale green, quartz sands which are located on the upthrown side of this faull, Leaching may be invoked to account for the northerly sands at section 15 but is probably not the explanation of sands underlying bryozoal ealearenites at section 19. The change to sands on the crests of these small folds seems more likely to indicate mild structural growth contemporaneous with deposition. From section 2 through section 22 the upper part of the Roguc Formation has beun leached of carbonate. Sandstones, sunds and clays form a sequence of beds which contain variable amounts of secondary iron-nxides and silica (Sect. 22, Fig. 3). Facies changes between sandstones, argilluceous sandstones and arenaccous Clays can he recognized. These rocks are traceable to calcareous counterparts, The uppermost beds of the Rogue Farmation south of Port Vincent consist of grey and hulf, medinm, quartz sandstones with interbeds of thin brown, green and buff arenaceous mudstones (Sect. 24, Fig. 4). They laterally grade to poorly- STRATIGRAPHY IN YORKE PENINSULA igo sorted, medium, quart” sands with granules near Devils Gully. Further south at section 26, the sunds are about 6 metres thick. These sands contain patches of cvetn colouring and are less sorted than the underlying grey quartz sands near the middle of the Roguc Formation. They can be traced through a badly weathered area between section 27 and the first small creek immediately to the north (Fig. 4), Near section 37 the sands laterally grade to calcareous and argillaccaus, quartz sandstones and arenaceous limestones which gradually dip below sea Jevel to the south. Clay minerals in the Rogue Formation are mainly montmorillonite, mixed layered montmorillonite and glanconite with variable amounts of illite, The zeolite clinoptilolite is fairly common in marine sands at the type section and very common in the upper part of the formation south of Black Point, Many slump-blocks consisting of parts of the Rogue Formation and overlying sands, clays and calorete are found between Port Vincent and section 23 (Fig, 3). The clays in the lower part of the Rogue Formation, often saturated with water, provided a slippage plane for these blocks, Subsurface and Correlation In the Black Paint well the lower 14 metres of the Rogue Formation catesist of alternating browu, moderately- to well-sorted, coarse quarte sunds with ovcasional pebbles, dark grey and grey, silty to very fine quartz sands and arenaceous, silty clays (Fig, 6). Occasional glauconiie pellets, pyrite, muscovite and lignitic fragments are found in these sediments. They contain a fauna of small foraminifera, ustracods, lamellibranch shells and fragments, sponge spicules and the gastropod Turritella wldingae. It is likely that a facies change takes placo in the subsurface towards the northeast because quartz sands predominate in the lower prt of the formation at Rocky Point. In the Black Point well the alter- nating sunds and clays are found at a stratigraphic Jevel similar to that of sands and clays constituting the lower part of the Rogue Formation near Port Vincent, Further south at the Adelaide Cement Quarry, about 9 to 15 metres of quartz sands overlic Permian basement in the subsurface. Thus, the alternating sands and clays to the north probably grade to quartz sands in the subsurface towards the south (Fig. 6). In the Troubridge well, marine pale und grey calearevus arenuceous clays between 192 and 204 metres constitute the upper part of the clay Facies and are correlated with the lower part of the Rogue Formation in other areas, Mostly grey and dark grey fairly well-sorted medium and coame quartz sands ure found between 35 and 69 metres in the Black Point well. The sands contain licnitic fragments and occasional marine foraminifera. At higher levels glauconite pellets and occasional Turritella are present. The sands otcur at a stratigraphic level similar to those constituting the middle part of the Rogue Formation in coastal cliffs south of Black Point (Figs. 3; 6), Further south, grey argillaceous quartz sands and silts between 186 and 192 metres in the Troubridge well are ahout time-equivalent to the sands constituting the middle part of the formation in the coastal cliffs (Fig. 6). In the coastal cliffs and the Black Point well these poorly fossiliferous and fairly well-sorted sands indicate a higher energy environ- ment than laminated to fnely bedded clays in the lower part of the formation, At upper levels these sands indicate a slighUy lower energy environment in the coastal sequence because they here become more fossiliferons and then are grada- tionally overlain by poorly-sorted, fossiliferous sandstones of Upper Eocene age in the upper part of the formation, The deposition of these sands lasted slighily longer in the Black Point well and they also careelate with Upper Eocene beds List WILLIAM J, STUART jn the upper part of the formation in coastal cliffs ta the south. In the well marine foraminifera of Upper Eocene age are rare below 55 meircs in the coarse sands whereas foraminifera of Oligocene age are fairly common at 53 metres in finer sands. The stratigruphic relationship of the sands in the well to those in the southerly eoastal cliffs suggests regression and probably still stand followed by a northerly component of transgression. Further south, the Upper Focene: beds in the upper part of the Rogue Formation in the coastal sequence correlate with the lower 6 metres of the Port Vincent Limestone in the subsurface at the Adclaide Cement Quarry and the underlying 9 to 15 metres of sand (Fig. 6), In the Black Point well the sediments between 35 und 82 metres mostly correlate with the Rogue Formation at its type area, Quartz sands above 55 metres in the well gradually fine upwards until pale yellowish grey calcarcaus very fine to fine quartz sands constitute the upper 18 metres of the formation, These sands correlate with the uppermost part of the Rogue Formation of Oligo- veme age and part of the Port Vincent Limestone of Oligocene and lowermost Lower Miocene ages in the coastal cliffs south of Black Point and in the Troy- bridge well (Fig. 6), Although erosion has removed most of thy Rugue Formation ® short distance inland and subsurface data is unavailable from arcas of possible occurrence, it is probable that most of the formation consists of sands and sand- stones similar to those both to the north and south. The maximum known thickness of the Rogue Formation, 52 metres, is found in the Black Point well. The formation becomes thinner to the south by lateral gradation to part of the Port Vincent Limestone and by depositional thinning of the lower part of the formation which documents the second ingressian of the Upper Eocene sea. At Muloowurtic Puint the unconformity at the top of the Rogue Formation suggests that thinning in the north was probably controlled by erusion or non-deposition prior to the deposition of the Port Vincent Limestone. PORT JULIA GREENSAND MEMBER OF THE ROGUE FORMATION Definition and distribution The name Port Julia Greensand was used by Ludbrook (1963) and later was formally designated a formation by Crawford (1965). The name was applied to a thin (46 em) bed of glauconitic sandstone which outcrops for ubout 200 metres near the base of coastal cliffs 250 metres south of Port Jolin jelly (Sect, 15, Fig. 3). The Port Julia Greensand (Member) as used in an expanded sense here (Fig. 3) is of Upper Eocene age and stratigraphically located near the base of a variable sequence of sandstones with occasignil carbonates, gliuconitic sandstones and mudstones, and caleareous claystoncs, All these rocks are here considered the upper part of the Rogue Formation, The separaliom ot the Rogue Formation consisting of mostly sands and sandstones from the two distinct rock-stratigraphic units, the underlying Throoka Silts in the northern area and the overlymg Port Vincent Limestone, is practical on the vast coast of Yorke Peninsula. Immediately south of sectivn 15 the Port Julia Greensand (in the sense of Crawford, 1965) laterally grades to less glauconitic quartz sands, A second alauconitic sandstone or niudstone is wow present 61 centimetres higher in the successian. Glauconitic sandstones and mudstones are found at about this strati- graphic level between Port Julia jetty and Port Vincent (Fig. 3), About 5 metres above these rocks in the vicinity of section 15, variegated red, green and buff sandstones and mudstones also are partly glauconitic and can be traced ititer- mittently in coastal cliffs. Both to the north in the Rlack Point well and to the south of Port Vincent in coustal cliffs the Port Julia Greensand has laterally graded SUKATIGRAPHY IN YORKE PENINSULA Lf to quartz sands which are found at a similar stratigraphic level, The Port Julia Greensand here is considered a mappable member of the Rogue Formution when expanded to include the variegated sands that include the lower glauconitic sandstones and mudstones at the type area. Lithelogy The Port Julia Greensand varies in composition between a green glauconitic quartz sandstone and an arenaceous glauconitic mudstone, It contains a fauna of numerous. lamellibranchs, gastropods, corals, bryozoans and other fossils. Occa- sional carbonate shells have been replaced by glauconite whereas internal and external moulds of fossils are predominant. Faecal pellets, pellets and internal moulds of foraminifera are common. Occasional opaque minerals are present but constitute less than 0-5% of the bulk compositinn, PORT VINCENT LIMESTONE Definition and Distribution The name Port Vincent Limestone is applied to a distinctive rock stvati- graphic unit consisting of bryozoal limestones which are exposed intermittently in coastal cliffs between Port Julia and Edithburgh (Figs. 1, 3; 4). In this arcu it gradationally overlies the Rogue Formation, An angular unconformity separites it from the Upper Pliocene marine sediments. An erosional remnant of bryozou! limestone at Muloowurtie Point is presumably of this formation; it unconformably overlies the Rogue Forniation. The type scction is located immediately south of Port Vincent at section 14 (Fig. 4}. The maximum thickness of the Port Vincent Limestone is 125 metres in the Tronbridge well (Fig. &), and was deposited during the uppermost Upper Eocene to Middle Mincene. The formation thins northwestward to about 40 metres in some bores at the Adelaide Cement Quarry. It also thins to the narth, where only 3 metres of bryozoul limestone are exposed 250) metres south of Port Julia and 6 metres thickness in the Black Point well. In the coastal area, the formation is mostly of Oligocene and Lower Miocene age whereas in the Black Point well and at Muloowurtie Point it is only of Lower Miocene age. Thinning is explained by the angular unconformity at the top of the formation, lateral gradation ta the Rogue Formation, and minor diastems within the formation. Litholozy The lower 9 metres or less of the time-transgressive Port Vincent Limestane is often arenaceous. Jt contains very tine to fie grains of quartz in the Trowbridge well: coarser vrains of quartz are found in the coastal area and near the base of bore No, 35 at the Adelaide Cement Quarry. Pale grey and grey-white bryozoal calcarenites varying in grain size from fine to very coarse are found in the Troubridge well. The finer grained calcare- nites contain variuble amounts of micrite with secondary growths of the sparry cement. Hard, coarse-grained calcarenites located at 152 metres and in the wpper 46 anetres of the formation are moderately-sorted and contain sparry cement eae of crystals 15-50 yw in diameter. The limestones contain rare glauconitic cliets. ¥ From the type section (14) to the vicinity of Gilcs Point, pale grey and clark yellowish grey medium to very coarse bryozoal calcarenites and calcirudites are traceuble. Although the limestones are mostly massive, they contain some len- ticular, thin beds containing numerous Chlamys and other fossils oriented along 166 WILLJAM J. STUART bedding planes. At lower levels yrey-white to pale pinkish white, well-sorted, bryozeal calcirudites contain bryozoal fragments ranging in size from 2 to 15 mm. Pale grey and grey-white bryozeal limestones laterally grade to hard pink, pinkish grey and orange-red calearcnites and calcirndites near the base of coustal cliffs in the vicinity of Beach Point and Klein Pomt (Fig, 1). The hard limestones ire usually associated with small faults, folds and fractures. The voids within the limestones are filled with sparry cement, In a few casey the sparite is confined to well-sorted limestone beds that can be traced laterally, It often accentuates small to medium scale, trough and tabular cross-strata. Aft the northernmost outcrop at Heach Point an erosional surface, considered a local diastem, separates hurd pink calcarenites from soft yellawish grey and grey-white culcarenites. The latter contain a few reworked pebbles of pink limestone which indicate an carly intro- duction of cement, On the other hand, the soft limestones gradually become harder and contain sparry cement indicating at least two pirical of cementation, Secondury cementation of limestone along fractures is iso common. About 6 metres above the base of pale yellowish grey and dark yellowish grey bryozoal calcaremtes between section 21 and Sheoak Flat (Fig. 3), thin- hedded limestones contaiy lamellibranchs and other fossils which are broken and show signs of abrasion, In contrast to these heds there are occasional inter- culated lenticular thin beds containing, delicate lamellibvanchs and bryozaans which show JitUe sign of abrasion. They are also found north of Sheoak Flat at section 20 where they form lenses at the base of the formation. On the down- thrown side of a reverse fault north of section 20, blocks of bryezoal calearenites have been rotated during faulting. Although bryozoans are the dominant biogenic constituents, foraminifera, echinoids, lamellibranchs, brachiopods and seaphopods are present, The echinoid Lovenia woadst and the lamellibranch Eotrigonia semiundulata are found in the bryozoal limestones of uppermost Oligovene and Lower Miocene Age. Locenia weodsi is very common in Lower Miocene yellowish grey bryozoal limestones at Muloowurtie Point, at upper levels in bryozoal limestones jinmediately south of Shepak Nat; in dark yellowish grey resistant limestones forming the upper parts of coastal cliffs intermittently between section 27 and Giles Point: in coustal cliffs at Rdithburgh. Near Muloowurtie Point a thin transgressive sand, maximtuny thickness L-2 metres, occurs att the base of an arenaceous. moderately-sorted, bryaznal calcare- nite (Seet. Sb, Fig. 2), They show a discordance of wbout 2” with the underlying Rogue Formation, The crosional surface is synclinal in form with a maximurn dip of 5° on the northern flank and less on the southern Hank. The basal sands are coloured buff and pale green, and grade from moderately-sorted fine sands ut hase to moderately- to poorly-sorted very coarse sands with granules at upper levels. Quartz, is the predominant constituent with erains of granite gneiss and arkasic sandstone. These constituents are also found within the overlying coarse wilearenites which contain intercalated thin beds of very fine to fine biogeni¢ caleurenites. OTHER EXPOSURES ON YORKF, PENINSULA Glaessner and Wade (1953), Ludbrook (1963) and Crawford (1965) lave shown or summarized the distribution of bryazoal limestones on Yorke Peninsula, At most localitics remnants of bryozaal limestones unconformably overlie pre- Tertiary sediments and basement. Hemmuuits located at Urania and in the sub- Surface at Minlaton and apper Yorke Valley (Crawford, 1965, Maitland Sheet) STRATIGRAPHY IN YORKE, PENINSULA 187 suggest that the Port Vincent Limestone overlapped al least the upper purt uf the Rogue Formation onto basement. Slight regression und stillstand ner the middle of the formation may indicate mild uplift and possibly slight erosion af the lower part of the formation prior to the major transgression. Renmants located on the west aud southern coasts indicate that basement highs were present during deposition of Upper Hocene and possibly lowermost Oligocene Rogue Formation, On the northern portion of Yorke Peninsula, remnants of a later marine deposit, uppermost Lower Miocene and Middle Miocene hryozoul limestones swith Lepidocyclina in their lower portion overlie basement in the Melton area, Lindsay (1970) has indicated that these Miocene sediments record ut least 2 murine transgressions in areas north of Mclton. The bryozoal limestones in the southern portion of Yorke Peninsula are hard, pink, red and white calearenites and calcirudites cemented by sparite. They are often arenaceous at Jower levels, Crawford (1965) formally applicd the name Fort Turton Limestone which was informally used by Ludbrouk (1963) for u remnant of bryozeal calcarenite about 15 metres thick on the western coast at Port Turton. On the northern part of Yorke Peninsula, the name Mclton Lime= stone, informally used by Ludbrook (1963). was formally applied by Crawfurd (1965) to “30 feet of conglomeratic, sandy, bryozoal eross-bedded limestones rich in Lepidocyclina”. The limestones at Melton are correlated with hard bryozoal limestones deficient in quartz between 82 and 91 metres in the Troubridge. bore. The arenaceous fraction of these limestoues and those at Port Hughes contain lithic and crystalline fragments derived from local source areas. ; Hard, pale brown, Lithothaninion limestones are located 3:2 kilamctres south of Cunclitfe at elevations not greater than 136 metres above sea level. They occur at about the same level as the Melton Limestone. Lithothamnion, which are characteristic of shallow water. indicate that the sea probably did not cover portions of Yorke Peninsula at greater elevutions. HALLETT COVE SANDSTONE Distribution and Litholegy Crawford (19635) has used the name Lallett Cove Sandstone for fossiliterous sandstones and arenaceous limestones of Upper Pliocene age on Yorke Peningulu. lu the Troubridge well arenaveous limestones of this age ure about 30 metres thick whereas on the eastern coast of Yorke Peninsula these rocks rarely exceed 3 metres. In the coastal area these rocks can be intermittently traced fron) Edith- burgh to immediately past the vicinity of the Port Vincent golf course. Over this distance the Hallett Cove Sandstone unconformably overlies the Port Vincent Limestone in the south und the Rogue Formation in the north, Near Giles Point, arenaccous limestones contain numerous oysters and other fossils (Tjudbrook, 1959). These oysters are often oriented parallel to bedding and show contact relationships ta one another with medium to coarse-grained quartz sand filling voids. Further north oysters are less numerous but Margino- pora vertebralis is common with the mollusc Anodontia sphericula, other mollusea, and bryozoans, Between Port Vincent and Sheoak Flat the Hallett Cove Sandstone has been considerably leached of carbonate, Inmiediately north of the golf vourse it is mainly medium to coarse quartz sandstone which contains occasional moulds of fossils, Immediately north of section 20 (Fig, 3) the sandstone becomes very argillaccous and termginous with a reticulate red and grey mottling, This (ua WILLIAM J. STUART Thottling results from a later lateritic profile. In coastal cliffs north of Sheoak Flat and on the northern side of the basiti marine sediments of Pliovene age are not known. Fluviatile rocks in this area may be partly of Pliocene age but there is no fassil evidence Lo confirm this. Qudtemary Sediments As the stratigraphic coastal profiles also show various Quaternary sediments url soil profiles exposed alony the east coust of Yorke Peuinsula, a general diseussion of these sediments is included here, Flovial-fan deposits unconformably overlie Tertiary formations immediately south of Rogue Point and in the vicinity of Ardrossan, Tepper (1879) applied the name “Ardrossan Clay and Sandrock” to these sediments which are probably more than 80 metres thick. The fluvial-fan deposits which have been descrihed by Ifowehin (1918) and Crawford (1965) are mainly arenaceous clays and quartz sandstones with lenses of conglomerate. The conglomerates contain pebbles of quartz, quartzite, feldspar, arkosic sandstone and fossiliferous siliccous sandstone. Tertiary formations and basement rocks constituting hills immediately west of the coast were the source for most of these pebbles (Crawford, 1965). Between Black Point and Giles Point fluviatile quartz sands and arenacesus clays overlie with angular unconformity the Hallett Cove Sandstone, Port Vincent Limestone and Rogue Formation. The angular discordance between fluvixtile sands and two of these formations can be seen between Giles Point and Wuol Bay (Stuart, 1969; chart 3D), This unconformity indicates that earth movements wero still taking place here during the Quaternary. Near Giles Point dark yellowish-grey quartz sands partly &ll solution cavitics in the Hallett Cove Sandstone and Port Vincent Limestone, Between Sheouk Vlat and Port Julia jetty a reticular red and grey mottling horizon iu fuviatile sediments also represent part of a laterite profile (Fig, 3). This profile: is not confined to these sands because underlying Tertiary formations hive been leached in several places and the mottled horizon also occurs imme- diately south of Sheoak Flat in sediments whieh are considered lateral equiva- Jents to the Hallett Cove Sandstone. On both the western and eastern sides of the basin thin lenses and layers of the mineral alunite are commonly associated with these profiles. Below the mottling horizon immediately south of Sheaoak Flat, enterolithie folds are found in green arcnaccous clays which contain lenses of alonite between bedding planes (Fig. 3). Above the mottling horizon dark vellowish-grey or buff quarlz sands contain authigenic ferruginous pisolites. Fluvial fan deposits near Ardrossan alsm contain this mottling horizon. In this area, the lateritic profile has been truncated and reworked pisolites above this surface were probably derived from areus immediately west of the present coastline. Arenavcous red and green clays unconformably overlie the earlier flaviatile sediments and Tertiary Formations (Figs. 3; 4). These clays fill solution cavities in the [allett Cove Sandstone and Port Vincent Limestone to depths greater than 27 metres (Stuart, 1969; Charts 3C;D). At a few Soculities, pink sands overlic these clays and calcrete soil profiles are well-developed. Fossiliferous limestones overlie either the Rogue Formation or Port Vincent Limestones on wave-cut platforms at the sites of Tertiary synuclines adjacent to Stansbury and Port Vincent. These limestones are tentatively correlated with fossiliferous sediments containing Anadara trapezia on the eastern side of the basiu where they have heen named the Glanville Formation by Firman (1966), STRATIGRAPHY IN YORKE PENINSULA 1h AGE OF SEDIMENTS Immediately west of Ardrossan and Price Townships, the basal fluviatile sediments have been correlated by Crawford (1965) with the Middle to Upper Eovene portiow of the Clinton Coal Measures in the northern side of the St. Vincent Basin. Although the Nuviatile sediments in the lower portion of the Black Point well do not contain lignites which could be used tor the purpose of palyno- logical dating, these sediments are likely to be of Middle te Upper Eocene age as they underlie marine sediments of earliest Upper Eocene age. The earliest Upper Eocewe murine sediments of the Muloowurtie Formation are found between 119 and 155 metres in the Black Point well. Their age is indicated by the first appearance (down the hole) of Truncoretalaides collactea Pinlay at 119 metres, The absence of Cloboquadrina primitiva Finlay (= Trun- coratalvides primitiva) whose faunal range partly corresponds to that of T. collactea, elsewhere during the Middle Eocene (Ludbrook, 1967) suggests an early Upper Eocene age, as the range of T. collactea extends inte the Upper Eocene. Althongh Ludbrook (1967, Fig, 3) included part of the Muloownrtie Fornation in the Middle Kocene, she has not published the evidence and Lindsay (1969) indicates that T. primitiva has not been found in the Sé. Vincent Busin. The Upper Eocene ranges of foraminifera associated with T. coflactea in this well and within the interval 232 and 259 metres in the Troubridge well are shown in Figure: 7, Wuntkenine ulabamensis which is a zonal fossil of the H- dlabamensis sone {Glaessner, 1951; Faunal Unit 1 of Garter, 1958) has nat been found in the wells, but only oeeasional specimens are reported from surface sections in the eastern side of the basin, The carliest Upper Eocene marine sediments accumulated during the upper- most portion of the lower subzone of the Turboretalia aculeata zone. which as recognized by Ludbrook and Lindsay (1969). The retnaining partion of this zone and the succeeding Subbotina linaperta zone which are present in the eastern side of the basin (Lindsay, 1969) can also be recognized in its western side (Fig. 7), Lindsay (1967; 1969) indicates that the upper boundaries of these zones are charactevized by the final appearance of their zonal fossils, The lower boundary of the T. aculeate zone can not be recognized, as marie sediments of this age have not heen deposited in this area, In the Troubridge well the first occurrence (down the hole) of S. linaperta is found 12 metres above the base of the Port Vincent Limestones ut 174 metres while T. @culeata was encountered at 180 metres, This suggests that the 8. lingperta Zone is present in this bare. A clay and thin limestone sequence between 186 and 232 metres is included within the upper portion of the T, acteleata Zone. In the Black Point well (Fig. 4) §, fineperta is first recorded rarely ut 55 metres in the Rogue Formation. This suggests that the remaining beds af the Muloo- wurtie Formation, Throoka Silts and part of the Rogue Formation were deposited during this time interval. Planktonics are usually very rare in the upper part of this interval in well-sorted sands of the Rague Formation which may explain the absence of 7 aewleata in thie portion of the Black Point well, The same [or- mations were deposited within this time interval in their coastal sequences except most of the Roguc Formation is of definite Upper Eneene age at its type area, Globigerapsis index Finlay is found near the base of the formation whereas S, linaperta and C_ cubensis are present about 6 metres below its top. In coastal cliffs between Black Point and section 24 south of Port Vincent, the final appearanves of both 8. cf. lineperta and T, aculeata occur within the upper beds of the Rogue Formation, Although sample interyals for the purpose of this study are widely spaced S. ef. inaperta and T. aculeata occur together WOKS BDOmaaNnOsL AUN SMVLS- -———= S313 bios 6961 SN A 7 oo A yi ANa003 : v3. uaddn 1334 S3¥13WOTIN “E =a Sige 3N3309170 9495 7 €21 0 3N3903 sI0qQWs OF ge i. pit é E ae NOLS3WI7 agmon LVW MOS wet NOL JIL YOMOO INA Sills VWOOuHL == = SS Sta aN3D0I1d a Ds FEE ER om NOILVWYO4 Jn9o4 7 — = : aie vs tes | | | | | LNIOd OVI ivi4 YvoaHS INZONIA L¥ad AMNGSNVIS ANUWNO INSW3O Salyiaa¥ qwoHs JogManouL VINSNINSd SAWYOA NOILDAS-SSO¥D STRATIGRAPIY IN YORKE PENINSULA V1 about 1:5 metres above the Port Julia Greensand Meniber at section 15 (Fig, 3), Immediately south of section 16, S, cf. linaperta oceurs without T. aculeata about 4 metres above this member, Distinctive benthonic foraminifera sted by Carter (1958, 1964) in Victoria are also present in the western side of the basin (Glaessner and Wade, 1958), Wade (1964) recorded Sherbornina atkinsoni, Asteriverina adeluidensis and Crespinina kingscotensis within the Muloowurte Formation located in the coastal area. In this area Maslinella chapmani and Pseudopolymorphing sp. (figured by Ludhbroaok, 1963) are also present within the lower half of this formation. In the Black Point well a similar assemblage oceurs within most of the Muloowurtie Formation. In this bore and the coastal section the Bolivinelle sp. (figured by Ludbrook, 1963) and juvenile specimens of Lamarcking cf. airensis are also present, Benthonic foraminifera which extend throughout the Upper Eocene and ure found in sediments of Oligocene age are shown in Figure 7. Near the top of the Mulonwurtie Formation in both the subsurface and in the coastal urca between Rogue Point and Harts Mine, foraminifera became very small and no diagnostic forms are present, The absence of diagnostic foraminifera in the strata may be due to regression that has taken place at different times within the upper half of the Muloowurlie Formation. On the other hand A. adeluidensis and Pscudopolymorphina sp, are not found above the lagooual Throoka Silts in tHe basal Leds of the Rogue Formation, From these considerations, the Muloowurtie Formation above 119 metres in the Blick Point well and the coastal exposures probably correlate with the Banded Marl Member and possibly the lowermost i 3 of the Soft Marl Member of the Blanche Point Mars in the casters side: of the basin. In the Troubridge well ( Fig, 6). A. adeluidensis also occurs rarely above T- collactea in glauconitic calcareous clays between 197 and 212 metres, Tn this well Pseudopolymorphina sp. and Lemarckina airensis are found between 229 and 259 metres in a limestone sequence. Ludbrook (1963) and Lindsay (1967) have recorded this Pseudopolymorphina sp. only from sediments which were onby deposited during the lower portion of the T. acculeata Zone. However in the Troubridge well this Pseudopolymorphina sp. is not present in calearcous clays between 213 aud 229 metres but occurs at 210 metres in fine calcarenites which were deposited during the upper portion of the T. ecculeata Zone, This indicates that the distribution of this Forarainifer is probably controlled by sediment type. L, ef. airensis occurs within the inwer belt of the Rogue Formation belwecn Port Vincent and Black Point and in the Black Paint well between 69 and 84 metres, In the Troubridge well the first probable occurrence of this foramintfer is at 95 metres in a clay sequence, Carter (1964) notes that the final appearance of L. airensis ovvurs within his Faunal Unit 2 which would also be close to the final appearance of this benthonic form in this area. On the bases of benthonic : planktonic foraminitera and stratigraphic position within the range of diagnostic planktonles, the lagoonal 'Vhrooka Silts probably correlate with the lower part of the Soft Marl Member and equivalents on the eastern side of the basin. The sands near the middle of the Hogue Formation bebveen Stansbury and Black Point are about time-cquivalent to the uppermost beds of the Soft Marl Member, the Chinaman’s Guily Beds and the lowermost portion of the Port Wilhmga Beds. While most of this sequence is regressive, its uppermest portion is considered transgressive, as shown hy a similar sequence encountered in the Black Point well where it now underlies sediments of Oligo- cene age. In this well the uppermost purtion of this sequence is an approximate time equivalent to the remaining sediments of Upper Eovene vge in the Port Willunga Beds, 172 WILLIAM J. STUART Lindsay (1967, 1969) has established three zones for faunas of Oligocene age in the eastern side of the St. Vincent Basin, The Chiloguembelina cubensis Zone and the Cuembelitria stavensis Zone haye been recognized (Fig. 7) within faunas in its western side, but the uppermost Oligocene Globigerina. euapertura Zone has not been recorded here. This is probably due to widely spaced sampling and very thin sequences that could be of this age, Lindsay (1967) indicates that the lower boundary of C. cubensis Zone is characterized by the finul appearance of §. linaperta while the upper boundanes of this zone and the succeeding C, statensis Zone are defined by the final appearance of the zonal fossils (Fig. 7). The overlapping ranges of Chiloguembelina and Guembelitria were shown hy Wate (1964. Table 1). The final appearance of Guembelitria is just below the Oligecenc-Miocene boundary { Wade, 1964, Lindsay, 1967, 1968). Between Black Point and Stansbury the C, ctibensis Zone and the C. statensis Zone are present within the uppermost beds of the Rogue Formation and the Port Vincent Limestone. In the Rogue Formation at sections 15 and 16 (Fig. 3) the local, final occurrence of C. cubensis ts tound about 5 metres below the top of the Rogue Formation. Immediately south of Shesoak Flat, it is now found just above the basé of the Port Vincent Limestone about 120 metres north of section 22. The uppermost occurrence of this fossil north and south of Sheaak Flat sugwests that the lowermost beds of the Port Vincent Limestone are about time-equivalent to the uppermost part of the Rogue Formation (Fig. 3), Further south at sectinn 27 (Fig. 4), C. eubensis is present 1-7 metres above the base of the Port Vincent Limestone. At these localities, G. exapertura, G, Irulloides, C. amplianertura, G. angustinmbilicata and Guembetitria stavensis and are usso- cigted with the zone fossil, C. cubensis. Occasional specimens of G. stavensis are present in the remaining heds of the Rogue Formation and Fort Vincent Limestone betweer Sheoak Flat and Bluck Point and the remaining outcrop of the Port Vincent Limestone immedi- ately south of Sheoak Flat. Planktonics are usually very rare with only occasional specimens of G. eugpertuta and G. ampliapertura. Within these beds, S. atkin- soué and Svoretkina perlata (Upper Rocene-Oligncene) avcompany C, stiavensts which suggests an Oligocene age (Fig. 7), The first appewrance of the echinoid Luvenia woodsi is found within the G. stavensis Zone on both the eastern and western sides of this basin. Between Port Vincent and Stuusbury rare specimens of Globigerinoides guadrilubus primordius (Banner and Blow) are present within the C, stavensis Zone. It is only known from Carter's Faunal Units 5 and 6 (Wade, 1964, Table 1). Immediately south of Beach Point at section 14, Operenlina victortensis oceurs within the upper third af the Port Vincent Limestone with recrystallized Sherbornina while midway between sections 25 and 29, the uppermost beds of the Part Vincent Limestone contain $. ctnzimarginata, 8S, atkmsoni and OQ. victorigensis, The assemblage of foratninifera (Faunal Unit 6, Fig. 7) suggests that the Oligocene-Miocene boundary is present within the Port Vincent Limestone al these localities. Further south at Klein Point, Ludhrook (1963) recorded 8, atkinsoni near the base of coastal cliffs and C. cuneimurginata ala higher strati- graphic Jeyel within the Port Vincent Limestone, This suggests that the Oligocenc—-Miocene boundary is also present at this locality. In the Troubridye well, the C. enbensis and G. stavensis Zones catmot be recognized within the Port Vincent Limestone because the zonal fossils are cither very rare or absent, The lower bonndary of Oligocene is tenta- tively placed at 174 metres where S, linaperta is first encountered down the bore hole (Fig, 6), From 165 to 174 metres, bryozval limestones contain a similar assemblage of planktonics as those recorded in rocks of Oligocene age in the STRATIGRAPHY IN YORKE PENINSULA 173 2a ian 2 3 154 Sede] uRT [Ba Sn¥ Bairnsdal i: W. danjukian Balecombian Batesford tar Lorgford ivelina eubetisis Zone OL 'ARepur]) eeucy Teuney avensis Zone Chiloy! Subbotina dinaperta Zone _ aculeates Zone s Turborotalia (7967 *BSGT teqyzeg) seg Temng oMoy BAT Lpkooptasy ByeTnotiden BitasopTay §(9z) (Gz) STSUsTLOpOLA DUT podedy: FST IeUpemo TiputoqaeyS ( FUOSITPAPe BUTTS GIayG if Bye_ied Buryyeans STreUPATION (1?) Wikessosopresd FSpISTaT, (de) “35 STWORwAy (7) SnerTe yo COPPSTEMET (eT) FTeuSypoossaTY CupUTIseAG (AT) TORNGEYS ETTSnT ey (9) TTSTepreleps WuraeATTeyey (GT) as WIpparoMsdopiery (71) Wepieydsty Seproutaestqom (€T) SIPBCOTpApeNO SSPyIaTASMTAOTH (ZT) SuSAeyS ELIT lequeng = (TL) Fie Te SurpsqaensoTtdg (OT) PSIeT SaTOGNS (4) smqasasrs HyasITSTH (,) Seprorsarsne PUTISsTIoTO (\y) BTreayoryyo BurszesiqeTo (4) WS BapIeTACTH (7) (€) (@) (t) outa gés and age of the early Secene 4o Miocene Formations located E Syserss tay SSpASTTIs Seplopejoaoomay, iste Wy LsuouBqoLy along the east ecast of Yorke Peninsula. Forawiniferal rx: WINSNINAd WHOL 1 WHY TYisyOo MOMISva ition Fig. 7, Non-depo PORT VINCENT LIMESTONE FORMATICN THROOKA SILTS MULCQWURTIE FORMATION \74 WILLIAM J]. STUART enastal sequences (Fig. 7). Although planktonics are very rave or absent above 165 metres in the Tronbridge eile occasional small specimens af G. stavensis only lave been recorded from 159 to 165 metres. The Oligocene Miocene boun- dary can be only tentatively pliced between 187 und 159 metres in this. well. The first appearance (down the hole) of the S. atkinsont accompanied by 8, cunei- pwrginida is at 137 mictres but these are extremely rare. Bryozoal limestones at 146 metres containing S, cuneimarginata, 8, atkinsoni and C. verriculata (all rare) muay be close to the Oligocene-Miocene boundary, In the Black Point well, quartz sands within the Rogue Formation hetween 34 and 55 metres are of Oligocene age (Fig. 1). The first appearance of ©, stacensis is at 36 metres, Within this interval planktonic forarminiferu in these suds are G, ouachitaensis, G, angiporaides, G. bulloides and G. angustium- bilicata. Cibicides pseudoconvexts is found rarely near the base of this sequenve whereas §. atkinsoni is present as high as 34 metres. Calearina verriculata is present belween 25 and 37 metres suggesting that the Oligocene-Miocene boun- dary occurs cither within the uppermost sands of the Hogue Formation or within ivenaceous bryozoal limestones (Port Vincent Limestone) at the top of the well. Single specimens of C. verriculate are recorded below 37 metres bat their preser- vution suggests contamination. ; Sediments of Oligocene age within the Port Vincent Limestone and the Heviie Formation are correlated with Oligocene scdiments within the Porl Wilhniga Beds in the eastern side of the basin. Inmmediately south of Muloowurtic Point (Sect ob, Fig. 2), limestones can- Laining Ihe association of §. atkinsoni, 8. cuneimarginata and C. verriculata are considered of Lower Miocene age (Faunal Unit 6). lt has been previously slinwn that these Hmestones and thin basal sands uncontormably overlie about 5 metres of beach sands constituting the uppermost beds of the Rogue Formation, The first fully marine bed just Shelcive these sands to the south contains $. Ginuperta and C. cubensis, This suggests that the faunas diagnostic of the C, cubensis Zone ald (3, stavensiy Zone are not present at this locality. Further south of Muloowurtie Point in the Black Point well the upper 3 muvtres of the Rogue Formation and lower 6 metres of the Port Vincent Limestone contain C. verriculata, 5, atkinsond is present near the top af the Rogue Pormistian whereas 8. cuneimarginata occurs rarcly in the Port Vincent Limestone of this well, The upper 9 metres of sediments in this well, limestones just south of Muloawnrtie Point and the upper beds wf the Port Vincent Limestone at localities immediately south of Beach Point are correlated with the Port Willunga Beds of lowermost Miocene age, ic, Faunal Unit 6. Tr the Troubridge well, Carter's l’aunal Units 6 and purt of 7 ure probably present between 116 and 146 metres within the Port Vincent Limestime. C. benriculata and QO, victoriensis occur wilhin Ubis interval whereas S$. atkinsani and $. cuneimarginata are found together in the lower 9 metres of this interval. Occasional specimens of Cdes, bisphericus occur between 97 and 122 metres, Limestanes below 122 metres also contain this pluriktonic fannie but their preser- vation suggests contamination, Lepidocycling within bryozoal limestones between 83 and 97 metres correlate with the lower portion of the Melton Limestone en the vorthern part of Yorke Peninsula. In this well, the interval from 83 to 146 metres within the Port Vincent Limestane are correlated with sediments of Lower Miocenc age (Taunal Units 6,7, 8 and part af 9) withie the Port Willunga Beds on the vastern side of the basin. In the Vroubridye well, the Lower Miocene-Middle Miocene baundury may be present in 24 metres of limestones above beds containing occasional Lepidocyclina, bul there is no faunyl evidence tu prove this, On the other hand, sediments of Middle Miocene age occur in the STRATIGRAPTIY IN YORKE PENINSULA v6 subsurface of the Adelaide Plains Embayment and the Melton area. Lindsay and Shepherd (1966) have shown that the Munno Para Clay Member of the Port Willunga Beds is of uppermost Batesfordian and lowermost Balcombian (parts of tuunal Units 9 and 10) Lindsay 11870) has also indicuted that the uppur portion of the Melton Limestanc is of lowermost Balcombian. The Balcombian is considered of Middle Miocene age (Carter, 1964; Wade, 1964 and Ludbrook, 1967). Lindsay (1968) also recognized sediments of Bairnsdalisn age (Waunal Unit 11) from this area, GEOLOGICAL HISTORY ‘Tertiary accumulation commenced ju the northern area with the deposition of Middle Encene fuviatile sediments, Streams flowing from rising highs on the northivest portion of Yorke Peninsula transported fine and coarse detritus to sinking areas in the St. Vincent Basin, Following the accumulation ot these Huviatile sediments, the ingression of the sea is documented by marine sediments (Mauloowurtie Formation) depasited dining the lower portion of the Turterotalia aculeatu. Zone representing earliest definite Upper Eocene age. The sea encroached onto the northern area of Yorke Peninsula, but did not extend onto its southerly coastal area. In the vorthern area, currents aud/or wave-action tended to even the topography of the sub- murine Hoor by transport of sediment to areas of lower energy during subsidence. A shallowing of the sea is indicated by the Quartoo Sand Momber of the Muloo- wurtic Formation, but since this portion of the formation was deposited over u Great area of the depositional high between Pine Point and Harts Mine, basin expansion continued here, Slight deepening of the sea north of the depositional high is indicated by the upper beds ut the Muloowurtie Formation while a high energy environment continued on its southern side. The Upper Eocene sea uniformly retreated from the northern urea and the region intnediately offshore from the present coastline in the southern area. This is indicated by the lagoonal Throoks Silts and poorly fossiliferous. arenaveous clays in the Troubridge well. After the accumulation of the lagoonal sediments, the Upper Eocene sea retumed to present coastal arcas and alternating clays and fairly well-sorted sandstones within the lower third of the Roguc Formation suggest an oscillating shoreline immediately west of the present coastline. High energy marine environments are documented by well-surted quartz. sandstone an the southern side of the depositional high and the area immediately south of Klein Point. Another retreat of the Upper Eocene sea, near the top of the Turhe- rotalia aculeata Zone, is indicated by quartz sands in the middle portion of the Rogue Formation in the southern arca, but the sea did not retreat past the present coustline as the sequence indicates a subsequent marine stillstand of short dura- tion. During this time interval, there is no evidence within the Rague Formation al Muloowurtie Point Lo suggest a retreat of the sea. The sea probably retreated from the northern area during the S,, lineperta Zone assugvested by the erosional surface separating Upper Eocene and Misrene strata. Non-deposition with minimal erosion probably took place during this hiatus because reworked foraminifera of Upper Eocene age have not been obsécved in sediments of Oligocene age in other areas. As the retreat of the sea continued in the northern area, a major advance of ihe sca had begun in the soullierns area. The sea continued to advance in this area doring the Oligocene (Chilaguembelina cubensis and Guembelitria stavensis Zones) and Miocene time. Sedimentological and palaececological evidence from this aren and other portions of the St, Vincent Basin, suggest that the sea during the latter zone 176 WILLIAM J, SPUART covered parts of the southern portion of Yorke Peninsula (Stuart, 1969), The favies relationships between the Rogue Formation and Port Vincent Limestone indicate 2 northerly component of this transgression (Fig. 6). The sea did not reach the vicinity of Muloowurtie Point until earliest Lower Miocene time as indicated by henthonic foraminifera within the Port Vincent Limestone. It is likely that by uppermost Lower Miocene time, the sea had covered most of Yorke Peninsula, as Miocene sediments (Melton Limestone and equivalents) ate exposed! in its northern portion, and slightly carlicr limestones are present in the subsurface at Minlaton and upper Yorke Valley. Available evidence in surface exposures and subsurface indicates a period ut erosion which took place between the accumulation of lower Middle Miocene and Upper Pliocene sediments in Yorke Peninsula area. The Miocene sea had retreated from known areas of marine accumulation and probably from the remainder of the basin as well (Stuart, 1969), During the Upper Pliacenc the sea returned to parts of Yorke Peninsula and # Narrow seaway wis present on its southern portion (Ludbrook, 1959). Another erosional surface between Upper Pliocene marine strata and ?Pleistocene fluyiatile sediments indicates another peiod of erosion. This was followed by the aceumu- lution of thiviatile sediments along the cast coast of Yorke Peninsula. A notable example of these are the fluvial-fan deposits (“Ardrossan Clay and Sandrock”) deposited near Rogue Pomt (Fig. 2) and in the Ardrossan area (Tepper, 1879; Howchin. 1918). They were derived from basement and Tertiary rocks constituting low hills immediately to the west of the present coast (Crawford, 1965), These deposits and the remaining Anviatile sediments now exposed in the coastal cliffs of the southern area were weakly laterized and there is evidence particularly in the Ardrossan area of more than ou svil profile. Green und red clays were laid down following still another period of erosion, Sub-Recent shelly sediments accumulated in areas now constituting synclines of Tertiary strata, particularly on wave-cut platforms adjacent to townships in the southern area. Caleretes were forme: in soil profiles during and efter the climax of Plejstocene accumulation in the ooastal ares. STRUCTUBAL DEVELOPMENT The study of Cainozoic strata along the east coast of Yorke Peninsula has done much to elucidate the structural history recorded here during the Cainozoic Era. Following the accumulation of fluviatile sediments in the vicinity of Black Point, the sepuration of a remmant of Muviatile sediments in the coastal sequence (fig. 2) from those in the subsurface (Fig. 6) indicates that either north-south pe Dortheast-southwest Faulting occurred in this area prior to the deposition of earliest Upper Eocene marine sediments. The dispkicement of beds was less than 60 metres, The accumulation of Tertiary sediments indicates that Yorke Peninsula can be sub-divided into blocks which are separated by linear elements (Fig. 1), Howeyer, it is apparent from the beds which form gentle synclines and anticlines that several mitior Fiult-lines were uctive dtiring times of more or less earth move- ment, so subdivisions into smaller blocks could be possible. Glaessner (1953) has previously shown that ancient faults (Sprigg, 1942) form the boundaries between areas of mild uplift and subsidence in areas east of the St, Vincent Gulf. The northern block (A) appears to be separate from the southern areas, as indicated by the accumulation of the Upper Eocene Muloowurtie Formation, Slight tilting of this block towards the St, Vineent Gulf and to the north is indi- cated by the absence of these beds on the western side of Yorke Peninsula and STHATIGRAPHY IN YORKE PENINSULA WT facies relationships of the high energy Quartoo Sand Member intertonguing with the main body of the Muloowurtie Formation in a northerly direction. The narth- ward tilting of this block is alse indicated by Facies of mainly quartz sands in the Rogue Formation grading to more carbonate-rich rocks in 2 northerly direction. South of Black Point the absence of the Muloowurtie Formation or exquiva- lents from the east coast of Yorke Peninsula suggests that a north-south fault-line is present in this area. It is difficult to imagine an irregular topography persisting in such poorly jndurated scdiments as the Permian, throughout the Mesozoic and curly Tertiary. This fault-line determined the boundary between more and less subsiding areas of accumulation. This explains the abnormal thickness of earliest Upper Eocene sediments under the western portion of the St. Vincent Gulf. This substantiates a statement by Crawford (1965) who considered that 4 fault-line was present in this area, The northern and southern blocks (A and B) acted as a single tectonic unit during the accumulation of the lower half of the Rogue Formation, The independence of movement between blocks A and B is demonstrated by mild uplift of the northern block while the southern. block was subsiding during at least the Oligocene. This is indicated by the unconformity between Upper Eovene and Miocene sediments in the northern area and the presence of Oligo- eene sediments in a conformable sequence in the southern area. Small pulses ot virtible subsidence took place during the accuroulation of Oligocene sediments in the Rogue Formation between Port Julia and Port Vincent as suggested by facies relationships of quartz sands grading to clays. These facies relationships eaiotee that the variable rates of subsidence occurred adjacent to east-west fault- ines, The tlting of the northern block and times of independence of the move- ments along the east coast of Yorke Peninsula suggest a southwest-northeast ancient fault-line located in the vicinity of Black Point (Fig. 1). This is also sub- stautiated by aeromagnetic data (Schoenharting, pers, comm. ). This fault-line is oe substantiated by a large synclinal structure between Rocky Point and Port ulia. The two southern blocks (B and C) which form the lower portion of Yorke Peninsula have also undergone variable rates of movement, The southernmost block C (Fig. 1) was a persistent structural high during most of the “Upper Eocene, sediments of this age are not present on this block. During the Oligncene, this block began to founder as remmants of rocks of this age are locuted there. inner sequences of Oligocene and Miocene sudiments accumulated on the landward side of the north-south fault-line adjacent to the east coast of Yorke Peninsula as shown by the transgressive Rogue Formation and Port Vincent Lime- stone. The northward component of this transgressive sequence (Fig. 6) also suggests that the relative rate of subsidence was greater parallel to and towards the present continental shelf; thus it is Jikely to be associated with larger seale epeirogenic earth movements, Gentle folding movements occurred along the east coast of Yorke Peninsula betsyeen the accurmulation af Miocene and Upper Pliocene sediments (Glaessner, 1953). The strata in several areas have also been faulted, but the displacements of beds are very small (Figs, 2. 3). However, the folding movements of the Cainozoic beds are dependent upon the movernents of linear elements within Cambrian and basement rocks as are also the faulted heds. Reactivated folding movements involved Plincene beds as can be secn imme- diately south of Sheoak Flat (Fig. at Between Stausbury and Giles Point (Fig. 1; Chart 3D shown by Stuart, 1969}, a soulhward component of tilting move- ments cam be recognized by unconformable relationships between Midcene, 8 WILLIAM J. STUART Upper Pliocene, and Pleistocene beds and also between beds of Pleistocene age (Stwart, 1969), In the Ardrossaat area, Anvial-fan deposits also indicate earth movements along linear elemeuts. ACKNOWLEDGEMENTS This paper was made possible through the cooperation and assistance of many people to whom I wish to express my gratitude. Considerable assistance was given by Professor M. F, Glaessner and Dr, Mary Wade of the Department of Geology, University of Adelaide, and by other members of this Faculty. I am indebted to Mi. RK. C. Sprigg, Beach Petroleum, for making available subsurtace samples from various wells, and Mr, A. 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W, Parkin), Acetate, is) , Hower W.. 1918. Notes on the geology of Ardrossan and neighborhood, Trans. R. Soe, §. Aust. 42, pp. 185-235. Linnsay, J. M., 1967. Foraminifera and stratigraphy of the type section of the Port Willunga Beds, Aldinga Bay, South Australia. Trans, Roy. Soc. 5. Aust. 81. pp, 93-109, Lixvaa¥, J. M,, 1968. Notes on Foraminifera and stratigraphy at the Grange aml Croydon hutex. Quart. Geol, Notes, Geol, Surv. S, Aust, 26, pp. 1-3. Tannsay, J. M,, 1669. Cainozoic Foraininifera and Stratigraphy of the Adeluide Plains Sub- Basin, South Avstralia. Bull. Geol. Surv, 8, Aust. 42. 60 pp. | Linvsay, J. M., 1970. Melton Limestone: Multiple Mid-Tertiary transvvessions, south-castem Gawler Platform, Quart. Geol Notes Geol, Surv. S. Aunt.. 53. Lixoxay, J. M., and Stmpamo, R. G.. 1966, Manno Para Clay Member, Quart, Geol, Notes Geol, Surv, S, Ast. 19. Luosruox, N. H., 1959. A widespread Pliocene molluscan fauna with Anadontia in South Avstralia. Trans. R. Sou. S. Aust., 82, pp. 219-233. Lupsnook, N, H., 1963, Correlation of the Tertiary rocks of South Australia. Truns. R. Sou, S. Aust., 87, pp. 3-15. . , Lupproorn, N. H., 1967. Correlation of Tertiary rocks of the Australasian région 77), 7-L9, in The Eleventh Pacific Sci, Gongress. Tokyo, 1966. Symposiim No, 25, Tertiary correlation and climatic changes in the Pacific, Sasuki Printing. ancl Publishing Go, Ltd, Seadat, apan. a mais N. H., and Lespsay, J. M., 1969. Tertiary foraminiferal zones in South Avstralta. *p. 366-374, in Proceedings of the First International ‘Confortme: on Planktonie: Micha. peal (Ktlited by Brénnimann and Renz) Geneva, 1967. , MecKre, Mow D., and Wer, Gorpow W., 1953, Terminology for stratification und cross- stratification in seclimentary rocks. Bull. geol. Soc. Am. 64, pp. 381-390, Spruce, R. C., 1942. The geology of the Eden-Moana Fault Block. Trans. B.. Soe. §. Aust... 66, pp. 185-214, Stuawr, Winwtas J,, 1969. Stratigraphic: and structural development vf the St. Vineent Ter tiwry Basin, South Australia, Unpublished Ph.D. Thesis, University of Adelaide. Terven, J. G. O,, 1879. Introduction te the cliffs and rocks at Ardroysun. Yorke'sy Pettinsula. ‘Trans. phil. ‘Suc. S. Aust. 2, pp. 71-79, Wavr, Mary, 1964, Application of the linewge concept to biostraligraphic zoning based on planktonic foraminifera. Micropaleontology 10, pp. 275-290. QUONDONG STATION, SOUTH AUSTRALIA: A FIELD CONTEXT FOR APPLIED RANGELAND RESEARCH BY SUSAN BARKER* Summary Sheep stations are the administrative units of the arid zone pastoral industry in southern South Australia. Their general nature, history and present circumstances are given, with particular regard for the native vegetation upon which their productivity depends, by using Quondong Station as an example. A study of the pastures of Quondong Station is presented, intended as a general field context to which research results may be related. The flora of Quondong Station is listed. The native pastures are classified initially into four main groups, and are then cross-classified on other features. Results are summarised in map form. QUONDONG STATION, SOUTH AUSTRALIA: A FIELD CONTEXT FOR APPLIED RANGELAND RESEARCII by Susan Banner? SUMMARY Sheep stations are the administrative units of the arid zone pastoral industry in southern South Australia. Their general nature, history and present circum- stances ate given, with particular reyard for the native vegetation apon which their productivity depends, by using Quondong Station as an example. A study of the pastures of Quondong Station is presented, intended as a general field context to which research results may he related. The flora of Quondong Station is listed, The native pastures are classified initially into. four main groups, and are then cross classified on other features. Results are summarised in map form. INTRODUCTION In recent years concerted efforts have been directed towards ecological problems associated with the arid zone pastoral industry in South Australia, Much of the research is still in progress, but some is already published (Lange, 1969; Barker and Lange, 1969a), Such papers are specialised, and it is necessary ta deserids the field context within which specialised advances must be inter- reted. F When sheep were introduced to arid Australia in the nineteenth century, their impact on the native shrubs was both sudden and disastrous, For example, Dixon (1880) and Woolls: (1882) describe the destruction of saltbush after only a few decades of grazing in western New South Wales, Arid zone shrubs are slow growing, long lived plants arepted to low rainfalls and slow nutrient cycling. As such, they are quite different from kinds of plants that evolyed under intensive grazing by ungulates. While climatic changes can gradually degrade arid zone vegetation for periods, the effect of haoved grazing animals on these vulnerable populations has had an inordinately destructive effect for such a short time span, Pioneers were concerned with expansion and development in the short term, rather than conservation in the long term. This attitude can be understood when one recalls the colonists’ ignorance about the Australian environment (Meinig, 1963). At the present time, disregard for long term conservation can no lounger be tolerated. It is imperative for the future of this State that the conseqnences of the pastoral industry be examined. The type of resource being used by the pastoral industry is described by reference to a single administrative unit, Quondong Station, where grazing has been more or less continuous since 1873. The situation here is similar to that on many sheep slations im this and other States; boundary fences cut across different vegetation, rock and soil types, and paddock size and shape is determined by the disposition vf a limited number of stock water pomts, often haying little relation to use of different pasture types. Under such canditions it is inevitable that, given free range over several square miles, stock will utilise and, in extreme cases, degrade certain types of vegelation more than others. In addition to the description of the current situation on Quondong Station, the history of the area is outlined to indicate how historical factors may have had an effect on the present pasture pattern. > Department af Botany, University af Adelaide. ‘Tvans, R. Sac. S. Aust. (1970), Vol. 94. SUSAN BARKER ARID SHEEP GRAZING AREAS = S = LAND OVER 300m. a Mae ali ADELAIDE A} =e station | — a DOG FENCE =| i / CD 0 100 200 vic, Fig. 1. Locality diagram. SITUATION AND ENVIRONMENT Quondong Station, covering an area of approximately 830 sq km, lies in the northern part of the Murray basin, south east of the Olary Spur, and almost equi- distant between Burra and Broken Hill (Fig. 1). The over-riding climatic feature of this area is the low rainfall, the average for the period 1955-1968 being 180 mm (Table 1). The occurrence of rain is most erratic, more so, for instance, than in the coastal arid areas of the State (Commonwealth Bureau of Meteorology, 1961). Although the figures are variable, it appears that on average most rain is received in May and least in October. QUONDONG STATION, SOUTH AUSTRALIA TABLE IL Rainfall at Quondong in mm (by courtesy of the Pastoral Board ) Feb Aug. | Sep. 1955 | OO | 871 63:5 | 38-1] 10 2l-1 | 28-2 i 68 1956 ) 0-0} 0-0 33:0 | 16-0 (373 | 43 | 198) O97 | 136 ek 0-0 | 64-0 43) 686] 10) 178) 46) 16:3] 2-8 958 1959 13| 13-0 | 23-6 oO} 11-9 0-0 | 142 7-9 43° 23-2 0-0 1960 | 4:3 TL SS] EH | 19-1 33/386 | 14-2) 88-7); OO | 36-3 1961 O-O | 11-9 1s3 | 27-7 56 0-0) 66 | 12-5 | 17-0 13) 645 | 1962 [59-2 ) GO. 22-4 0-0 | 32-5 66) 23) 15-8 0-0 7-9 O-0 1963 | 29-6 OO | O08 | 22-4] 45-2) 41-7 |27-8 | 16-8 0-0 | 12-7 2-5 1964 [108 Off OO | 122] T4] 53] 0-0] 16-2, 81d] OH) TH 1965 | ODO — — | 0 aS | 132/153) 13-7 | 16-8 H() 71 1966 S1 10-8 Sl! OO 16-0) 11:7 | FL 0-0 | 11-9 Od) 15-2 1967 81 36-3 48° 0-0 4-1 23.) 2-8) 16-8 $1 0 0 | 1968 | 61:0 | 1-9 hed 27-2 27-2.| 26:7 |30-7 | 15-2 (ed) fied on) _., LP: j—___] Mean [148 | 183 | 145 | 10-0 | 27-5 | 18:0 )13-7 | 13-2) Leo 76 | 12-4 Dee. 181 Total 10 | 316-1 GO | 218-2 24-4 | 200-0 B4] 112-8 0-0 | 169-9 29-2] L77-8 70-9 | 217-6 11-7 | 215-7 180} 153-0 27:2 97-3 44-2 | 151-2 OO S18 fred | 278-0 18-6 | 179-7 Records of wind direction are available for Yunta and these display condi- tions generally applicable to the plains lying east, During the warmer months the prevailing winds are from the southerly quarter, whereas in winter, winds are more frequent from the north west (Table 2). TABLE 2 Ge Vrequeney of Wind Direction at Yunta ut 900 hr (by courtesy of the Bureau of Mctearology) YUNTA 1962-63 Jan. | Feb. | Mar. Apr. | May | June | July | Aug. | Sep. | Oct. | Nov. | Dee ‘ N 3 9 3 2 l 7 2 3 7 3 1u 12 NE 14 7 2 i 6 10 8 3. 3 3 Td 17 7 E 2 1 0) 2 0 0 2 0 1 a a ct SE 45 54 54 30. 20 2, & |; OI rd 34 24 51 8 ) 0 a 3 5 0 2 3 2 83 1 7 fj sw 13) 18 17 28 20 17 18 18 27 24° 26 12 Ww 2 0 0 0 5 5 $ & a 3 0) 0 NW 16 9 13 14 24, 32 48 36 25 18 12 7 CALMS | 5 2 8 19 15 29 24 18 3 i) 2 5 Temperature data are shown in Table 3; the hottest months, Jannary and February, achieve maxima of 32°C and the coolest months, June and July, 16°C and 14°C respectively. Extreme maxima and minima indicate the range of temperature which can be experienced by the region, Such meagre meteorological information is typical for most sheep stations. The geology af the area is imperfectly known (O'Driscoll, 1960; Ludbrook, 1961). Proterozoic and Palaeozoic basement rocks outcrop in the Mount Lofty Ranges and the Olary Spur forming a rim to the north of the Murray Basin. Quondong is about 52 km to the south-east of this outcrop and is situated on the LKS SUSAN BARKER TABLE $3 Temperature in °C for Yunta (by courtesy of the Bureau of Mcteorology) YuNTA Fob. Av, Max, | 82:2) 32-2 23-8 | La4 16-1 Ay. Min. | 14-1] 14-4 $2] 8-6) 3-3 Av. Mean | 25-3 | 23-3 do-b | 12-5! 10°) xtreme : Max. Avie! | 4363 | 4066 | 33-9 ) 27-8 | 23-9 | 22-8 “S| ORG aed) | 4203 | 44-4 19A1-64 OF i. Date 2/'60 |28/°65/ 18/63] 2/'54 | 1/58 |19/°60/27/'8O 11/59 29/65 20/"65 AOI BS | 1H)" = ai _ | -_ -_ Extreme | ! | Min. fi? | ded 1:1 |. 3-9. 6-7 |- 6-7 | 8:0 0-3-1 T-)| Ut) 1-8 1951-65 Date | 1/56 29/68 | 23/'66 | 15)°08/24/'67 |17/'59/9-L10/| 8/62 27/84] 4/"HE | BPE jena . 759 | \ infill material of the Basin, consisting of Tertiary and past-Tertiary littoral, marine and freshwater sediments, which in turn have been overlain by Recent acolian deposits (O'Driscoll, 1960; Firman, 1965). This lack of geological information is not general, however, and for sheep stations situated where there are major rock outcrops, the information available is as good as that for the wetter parts of the State, There is little detail in the literature concerning the relief of the area and the following new observations are presented. The gencral elevation falls 78 m in a south-easterly direction from the north of Ki-Ki Paddock, to the south-cast corner ol Drayton Paddock. Topographically the station may be divided into two regions north and south of a Jine which joins points A and B in Fig. 3. The principal ridges and drainage lines also shown in Fig, 2 have heights relative to each other vurying between 1m and 7 m. To the north, the country is a gently undulating outwash plain of the Olary Spur, traversed by broad ill-defined watercourses or washes, the intervening areas being occupied by low calcareous ridges and Recent sand dunes. There are two main drainage systems in this region; one flows from north to south in Record, Sixty, Sergeants, Well, Ki-Ki and Eighty paddocks and the other fows from west to east through Sergeant's and Swamp paddocks. The two systems mingle and lose their identitv in Georges and the Boundary paddocks. Only in the watur- course running through Ki-Ki and Eighty paddocks has gully crosion proceeded to the extent that parts of it could be regarded as a creek, with banks and a flat sandy bed (PL. la). itis probable that this has occurred subsequent to sheep being depastured in the area, as a result of increased run-off due ta compaction. This phenomenon has been observed elsewhere (Jackson, 1958). The ridges, which are old dunes, haye solonised soils, containing a high proportion of calcium carbonate both in the A horizon and in the lower layers, where nodular or massive calcrete occurs, This soil type is classificd as Gel, 12, according to the Factual Key (Northcote, 1965). The occurrence of polygonal ie a ground in these soils has been reported previously (Barker and Lange, L968b )- South of the line A—B the ridges and dunes are more numerons and the broad alluvial expanses of watercourses are absent. The drainage lines are rélatively small and are radial, draming into claypans and other low-lying areas. QUONDONG STATION, SOUTH AUSTRALIA 183 7 iim TOPOGRAPHY OF QUONDONG STATION | / — p ‘eu Ridges fee Drainage lines | f va {iein Tres Escarpments / Foal > Depressions i, PADDORK . f | aan } y IT \ et 1 iy I a rs AtKTM A a 5 f jes necana “4 uf S, Fapooce aya” | 1 PAROS - iNuus 4 » 4 EIDMTY eu ke 7 4 4 No A he ragnock ye " \ 4 / mS mo i_/ _ | Hi are WELL ‘s, “\ FaBBOCK aa \ 4 tte Fees ‘on! ~~ STROTANTS Re ens ._ ~~ oS ahi. g om, “NW ROUND ART =i . + Pe fo pappore 2 2 4 Oppiae km Map compiled from uncnntralled sara! phoragraphi 4 — PARKER'S: HAS Os i Fig. 2. Map of Quondong Station, showing principal topographic features and bench mark heights, 184 SUSAN BARKER Seme of the claypans have lunettes along their eastem margins. These may be an indication of a higher rainfall regime in the Recent pust, as lunettes are apparently formed by a combination of wave action on lake shores during wet winter months and deflation from dry lake heds during the summer (Campbell, 1968}. The current rainfall would be insufficient for water to fie in the Quondong claypans for any length of time. The Far south cast of the stalion is occupied by a continuous area (some 35-30 sq kin) of deep sandy dunes of Recent veolian origin, oriented in an eust- west direction. They can be recognised from the vegetation map by the occur- renee of mallee; isolated sand dunes appear as far north as the Well paddock, These have soils classified as Uc5. 11. Descriptions by O'Driscoll (1960) of the hydrology of the north of the Murray Basin are based on information fram a few bores, The salinities of the fossil waters examined on Quondong are too high to allow for their use as stock water. All stock water is, therefore, derived from surface run-off stored in earth dams. The position of these in relation to the topography is shown in Fig, 2. All the dams are watering points for stock, and some of their water is piped to troughs in parts of the station which would otherwise be ungrazed. The preceding account emphasises that a sheep station is not hornogeucons in terms of landscape, Design of experiments in such a variable situation is thus difficult; also, extrapolation of findings from one region to another must be at the level of principal rather than detail. VEGETATION Over a period of one year, March 1967—April 1968, plant collections were made on Quondong, These collections, consixting of some 150 species, are now housed in the State Herbarium of South Australia, Subsequent experience on uther stations with a herbaceeus rather than a shrub vegetation has shown that plant collections often cannot be completed for several years. The map at the end of this paper assembles and displays the outcome of the work upon which this paper is based. Sixty extensive ground traverses were nveded to rectify adequately an initial interpretation based on aerial photographs. The classification thought best suited for analysis of the system was one using character trees first, then cross-classifying successively in terms of character shrubs, then herbaceous components, This kind of clussification avoids the necessity to draw discrete boundaries as between two mutually caclusive classes. and permits mapping which expresses gradi¢nts of change. Details concerning the mep uré given with the explanatory legend accor- panying the map. Compared with some stations the broad vegetation pattern is simple on account of the comparative geologic and topographic uniformity, There are four principal vegetation types. These are (L) Casvarina cristata (black oak) woodland (IL) Mallee (JIL) Callitris coltemellarnis woodland (1V) Acacia anenra_(mulga) woodland, In addition, section (V) includes a miscellany of local but distinctive vegetation types charactevistic of water-collecting areas other than the major watercourses or wishes. (1) Casuarina cristata (black oak) woodland, found on the old calcareous dune ridges north and south of the line A—B, occupies by far the greatest area of the station and is extremely dense in parts, particularly in the south. Although nuiny groves of this tree are dead, especially in Gearge’s paddock, it is regener- ating freely by means of suckers all over the station, even in apparently dead stands (PE 1b), ‘his is of interest as workers in ather parts of the State (Tall, Specht and Eardley, 1964; R, M. Purdic—personal communicition) imply that QUONDONG STATION, SOUTH AUSTRALLA 185 under heavy stocking or in times of dronght Casuarina suckers are grazed down hetore they can reach maturity. Other tree species found commonly throughout this woodJand are Myoporum platycarpum, freely regenerating from seed (¥1, le), contrary to observations by Hall et al. at Koonamore, and Heterodendrum oleaefolium, the regenerating suckers of which are grazed down as m other parts of the State (fall et al., 1964; BR. M. Purdie—personal communication). Eremophila longifolia (emu bush), Acacia ostcaldii, Pittasparum phylli- raenides (native willow, apricot), and Santalum acuminatum (quondong) are rather less common, The shrub layer consists principally of Kochia sedifolia (bluebush) with K. excavate var. trichoptera and Bassia diaeantha. On the tops of the calearcaus ridges there is often very little else, but other shrubs fairly common Jocally are Prilotus obovatus, Olearia muelleri, Scaevola spinescens, Cratystylis conocephala, Cassin nemophila var. nemophila, C, wethophile var, coriacea, Acacia colletioides and Templetonia egena (desert broombush), with Kochia brevifalia, K. georgei, K. astrotricha, Lycium australe (hexticn), Nitraria schoberi (nitrebush), Eremo- phile glabra (tar bush), E. scoparia and Zyzophyllum aurantiaeum less common. C. nemophila var. zygophylla, C. nemophila var, platypoda, Acacia hakeottes amd Ptilotus alriplictfolins are rare, Atriplex wesicaria (bladder saltbush) occurs only in small quantities; an apparently isolated area in Ki-Ki paddock is the southernmost extension of sult bush from the floodplains of the Olary Spur on the adjacent Lilydale Station, iow hare on Quondong, A. vesicaria is associated with low lying areas in the south, Kochia pyramidata, recogniscd as a symptom of degraded arid pastures in the north-west of the State (Jessup, 1948; Correll, 1987), does. not occur exten- sively ore Quondong Station. Rhagodia spinescens var. dellophylla, Rh. nulans and Enchylaena tomentosa are found throughout the Casuarina woodland, but mainly under trees and in drainage lines. (11) The mallees, Eucalyptus oleosa and F. gracilis on the dunes in Draytou paddock, a northern extension of the Murray Mallee, haye a sparse shrub under- storey. Triodla irritans (porcupine grass) provides most of the ground vover: further north there is less poreupine grass und shrubs are present, including Chenopodium desertorum, Grevillea hueglii, Hakea leucoptera, Olearia pirme- lioides, Kochig triptera var, erioclada and K. sedifolia, and the herb Boerhavia diffusa, In places the mallee intergrades with dunes carrying Casuarina cristata and Hakea leucoptera, with Kechia tomentosa and K, triptera var. erioclada. (TIT) In two small areas of the station sand dunes are occupied by Cullitris columellaris, with Hakea leucoplera, Kochia brevifolia, K. triptera var. erioclada and the grass Eragrostis laniflora in the understorey. (IV) Acacia aneura (mulga) stands are im the drainage lines and water- courses which dissect the Casuarina woodland in the northern half of the station. Timber is much less dense in these areas and in the well defined watercourse of Ki-Ki and Eighty paddocks includes Acacia victoriae as well as other tree speciés mentioned in the description of the black azk woodland. Shrubs and forbs in these arezs are Eremophila maculata Atriplex limbata (native fuchsia ) A. spongiosa E, oppositifolia A. angulata Bassia pavadoxa A. lindleyi 186 SUSAN BARKEK A. acutibractea Solanum esuriale Acacia burkittii Cassia nemophila var, nemophila C. nemophila var. coriacea. Swainsonia viridis Ixiolaena leptolepis Erodiophyllum elderi (Koonamore daisy) Senecio magnificus Pterucaulon sphacelatum Hibiscus krichauffianus H, farragei Sida intricata S. corrugata S. corrugata var. angustifolia Herbaceous plants found in watercourses and wash areas are Stipa nitida Cymbopogon exaltatus Eragrostis dielsii E, setifolia Chloris acicularis Enneapogon avenaceous E. cylindricus Panicum. effusum Danthonia sp. Vittadinia triloba Brachyscome ciliaris Helipterum floribundum. Calotis hispidula Nicotiana goodspeedii Convolvulus erubescens Goodenia subintegra Chenopodium pumilio Arabidella. trisecta Malvastrum spicatum Morgania glabra (V) Although many of the above watercourse species occur along tracks, in sinkholes, drains and in the vicinity of dams, others are quitc specific to sink- holes and similar small depressions— Gilesia biniflora Alyssum linifolium T'eucrium. racemosum Euphorbia eremophila Oxalis corniculata Marsilea drummoniii: (nardoo) Eriochlamys behrii _ Centipeda. thespidioides Abutilon malvifolium while some are specific to areas around dams and the drains leading into them, for example, Centaurium spicatum Glinus lotoides Gnaphalium luteo-album Tetragonia tetragonoides (native spinach) Portulaca oleracea Verbena officinalis Minuria leptophylla Atriplex eardleyi A, spongiosa Babbagia acroptera Bassia brachyptera Tribulus terrestris Plantago taria. In addition, alien weeds are to be found only in watercourses and other water-collecting areas: Xanthium spinosum (Bathurst burr) Salvia lanigera Tnula graveolens (stinkwort) Nicotiana glauca (tobacco bush) Centaurea melitensis Citrullus lanatus (bitter melon) Cucumis myriocarpus (paddy melon) Asphodelus fistulosus fal onion ) Sida leprosa var. hederacea Diplotaxis tenuifolia Heliotropium supinum H, europaeum Polygonum. aviculare Chenopodium murale. DUONDONG STATION, SOW)VH ALSTHALIA VR7 These are obviously very dependent on additional water for survival and are unlikely to spread ta drier sites, Swamps near Centenary Dam and Mick’s Swamp Dam are churacterised by Muehlenbeckia cunninghamii (lignum), Chenopodium nitreriaceum and Ere- grustiy australasica (canegrass), while parts at the southern clay pans have Disphyma australe (pigtace) and Pachycornia sp. growing on thom. GRAZING HISTORY Early pastoralists in South Australia relied upon supplies of natural surface water for stock, with the result that grazing in arid country began in the Flinders Ranges and Olary Spur. The northern part of the Murray Basin was without surface water (S. Aust. Parl, Paper No. 57, 1885-66), so‘ this region was not opened up until the 1870's, The present Quondong Station was originally three administrative units; a run known as Quondong Vale (including Brands paddock, S.W. Boundary pad- dock and all paddocks to the north of these), part of the Drayton Run (now Red Dam and Drayton paddocks) and part of the Pine Valley Run (Balara, Yabba, Weary, and Parker's paddocks ). Although the lease of Quondong Vale was first acquired in 1873, it is unlikely that any grazing occurred during the frst few years as there would be no perma- nent water until 1876 when a Woolshed Dam in the south of George's paddock was dug. A further seven dams had been dug by 1880 and eight more and the Engine Well were complete by 1890; if sufficient rai had fallen during this period to fill the dams, then considerable areas would have heeome available for azing, - The watercourse or wash country close to the homestead in George's, Swamp, Brand's and the Bowndary paddocks, which were fenced prior to 1884, was probably the only area in constant use for shepherding sheep up tu 1898. The surveyor deseribed this area as “fair pasture; open country cavered with various bushes and bluebush plains with a little grass; greater part heavily timbered with black oak cte.” There is evidence that in the country north of this (now Sixty, Revord, Eighty aid Ki-Ki paddocks) the lessee had difficulty in establishing dams; also as the vegetation was described as heavily timbered with only » few open blucbush, plains, it was probably only lightly grazed, if at all. It is apparent from correspondence with the Surveyor General's Office. that the lessee had other problems, By 1990 the north of the Murray Basin was over. run by rabbits and dingoes (see also §, Aust. Parl. Paper No. 33, 1891) und hy 1892 was drought stricken. No rain had been received tor twelve months and leases to the south had been abandoned, Although the lessee said he would not restock the country as his lease was about to expire jn 1894, he continucd te run sheep until 1896, when he finally abandoned the country. He had 340 sheep watering on the Engine Well at that time in a vain attempt to convince the Government Analyst that the water was not too saline for stock, It may be this event which accounts for the effect seen in Pl. 1c) where close to the Engine Well, George's paddock is denuded of bluebush. . Less is known about the Drayton and Pine Valley runs; as these two leases were taken out together in 1874 by the sume person they were presumably run as # Single unit, This area corresponds to the southem topographic region. The sirvevor described it as “Poor pasture; undulating; light red sandy Inam with occasional clay flats, limestone rubble on the surface... , dense black oak, mallee, sandalwood, and various bushes, undergrowth and saltbush.” Six dams and a well were dug by 1890. Embankment Dam was the fist and shepherding was certainly 18s SUSAN BARKER carried on there in the nineteenth century. Weary Dam, dug in 1881, was used to water bullock teams crossing trum New South Wales to Burra. As the pasture was assessed as heing poorer than that further north, sheep on the Drayton-Pine Valley Run would have been more susceptible to the drought prevailing by 1891, leading to the abandonment of parts of it only 17 years after the lease was first taken up, It fern reasonable to assume that the northern part of Quondong Station (Quondong Vale) was more heavily grazed during the nmeteenth century than the southern part ( Drayton—Pine Valley). Whatever the actual stock numbers may have been in these two areas, it seems certain from Goyder’s remarks (S, Aust, Parl, Paper No, 82, 1867) that the practice of shepherding was. far more desteuenve thun the present one of allowing sheep to range freely within addacks. r Between 1901 and 1909 one lessee acquired the leases described above now comprising Quondong Station; since then six more dams have been dug sane mure paddocks fenced, thus allowing more extensive use of pasture. ‘The regular use of the country for shcep grazing probably dates om about 1910. Information in the Department of Lands indicates thut the heavier use of the watercourse country to the north of the homestead continued for at least some of the past 60 yeurs, the Drayton—Pine Valley section being referred to on one occasion as showing no sign of erosion or overstecking, as water sppplics were too small te permit that, whereas there are implications. that some of the watercourse pad- cocks had been overstocked. Historical records for other stations are certainly more complete, particularly where the lease has been held by one family for several generations, Although the present manager of Quondong is interested in the station's history, the lease has been previously held by several others and recards have been mislaid or destroyed, It would be of immense value in long term assessment of arid pasture conditions if all station records, including rainfall data, numbers of stock carried, photographs, could be maintained in Pastoral Archives, DISCUSSION Some ot the effects of using arid vegetation as sheep pasture are beginning tu be understood. The break up of the soil surface and destruction of a lichen crust. immediately lays the soil open to erosion by wind wud waler even where yege- tation remains. Nutricnts are removed with the top layers of soil. It has been sugyested by Correll (1967) that the loss of nitrogen in this way has encouraged the change from Kochia sedifalia to K. pyramidata shrubland north-west of Port Augusta, While the surface layers may be pulverised, lower soil layers round water points and along sheep pads become hihly compicted, promoting run-off, and allowing subsequent storage of water in dams, which would otherwise enter the soil (Jackson, 1958}, Such physical changes as these are clear within a short period of time and are now, therefore, predictable tor all sheep grazing areas. However, the longevity of arid zone plants (Correll and Lange, 1966; R, M. Purdie—personial commnni- cation) means that changes in vegetation (apart From its complete removal an overstocked situations) will be much slower to appear. and consequently with our present state of knowledge, much less predictable. Not only does arid vege- tation vary all over the State according to environmental differences, bul even on one station the vegetation pattern will differ from paddock to paddock and within individual paddocks. The position of water points in paddecks will obviously affect the utilisation of these different pasture types, for it is well known that sheep degrade vegetation close to water before that in other parts of QUONDONG STATION, SOUTH AUSTRALIA 189 paddocks { Osborn, Wood and Paltridge, 1932; Barker and Lange, 19694}. Sheep azing habits are not yet fully understood, but general observations indicate that Sheep referentially graze watercourse vegetation and tend to graze inte the wind lang the southern edges of paddocks. The imiform use of pasture is made very difficult in areas where paddock size and shape is strictly controlled (as at Quondong) by the number of suitable catchments for dams and the water-holding capacity of the substrates. In other arid areas of South Australia plentiful bore water and piped river water allow strategic positioning of tron ehs in small paddocks, thus encouraging stock to utilise pasture they might otherwise ignore. The descriptions and comparisons made in this paper exemplify ihe multi- variate situation which arid rangeland ecologists have to understand before changes in the vegetation can be attributed to stocking. The overall vegetation pattern on Quondong Station is similar to that in the immediately snrrounding areas of the Murray Basin, but differs from that found elsewhere in arid South Australia, Tt must, therefore, he understood that plants which may indicate degeneration in one part of the State do not necessarily indicate degenerution in other areas. This raises an important point, Results or observations gained from one location in the arid zone must not be extrapolated injudiciously. For example. comments made by Hall, Specht and Eardley (1964) om the regeneration uf Caswarina cristata and Myoporum platycarjyum at Koonamore, and by Jessup (1945) on the spread of Kochia pyramidata in overstocked situations in the north west, are at variance with observations made on Quondong. Ceneralisations made on the basis of particular vesults have introduced a great number of misleading statements into the literature. A modern approach to the solution of management problems associated with watural ecological systems like these native arid pastures is to use simulation studies. These depend on the definition of parameters which describe the various aspects of the total system. At present it is difficult to see how precise parameters can be derived for such extremely variable vegetation. ACKNOWLEDGEMENTS This work was made possible by financial support from the Rural Credits Develapment Fund of the Keserve Bank of Australia. The wathor would like to thank Dr, R. T. Lange of the Botany Department. University of Adelaide, for many helpful discussions and critical reading of the text, Dr Hj. Eichler and the staff of the State Herbarinm of South Australia for advice concerning the floristics and officers of ihe Department of Lands, the Pastoral Board, the Bureau of Meteorology and the Electricity Trust of South Australia for help in obtaining information. The author's sincere thanks are also due to Mr, and Mrs. A. D. Findlay of Quondong Station for very generous advice and hospitalily while the work was ih progress. REFERENCES Bankes. S., and Lance, R. 'T., 19694, Effect af moderate sleep stocking on plant popelations of a black oak-bluebush assouiation, Aust. J, Bot 17: pp. 527-37. Barwen, S., and Lance, R, T., 1969, The occurrence of polygonal pullerned vround iy Ne arid zone of South Australia, Trans, Roy. Soc, Aust, 93: pp. 153-155. aaa aoe 1968, Lunettes in southern South Australia. Trans. Roy. Suc. §. Aust. 92; pp. 85-109, Conrunr, RK. L., 1967. Studies on the niltogen economy of semi-arid yeeetations at Yudiapinna Station, South Australia, M.Se. Thesis, University of Adelaide. (Vnpublished ). 490 SUSAN BARKER Correct, R, L., and Lance, R. 'T., 1966. Some aspects of the dynamics of vegetation in the Port Augusta—Iron Knob area, South Australia. Trans, Roy. Sac. $, Aust. $0; pp, 41-43. ComMMONWEALTH Bureau oF Mereoroiocy, 1961, Climatological Survey Region 13—Whyalla, South Australia. Director of Meteorology, Melbourne. Drxon, W. A., 1880, On. salt-bush and native fodder plants of New South Wales. Proc, Roy Soc. N.S.W. 14: pp. 133-143. Firman, J. B., 1965, Late Cainozoic Jacustrine deposits in the Murray Basin, South Australia, Geol. Surv. of S. Aust., Quarterly Geol. Notes 16. Har, E. A. A., Specur, R. L., and Barpiey, C. M., 1964. Regeneration of the vegetation on Koonamore Station Reserve, 1926-1962, Aust, J. Bot. 12: pp, 205-64. Jackson, E, A., 1958. A study of the soils and some aspects of the hydrology at Yudnapinna Station, South Australia. C.S.I.R.O. Diy. of Soils. Soils and Land Use Series 24 Jessup, R, W,, 1948. A vegetation and pasture survey of Counties Eyre, Burra and Kimberley, South Australia. Trans. Roy. Soc. S. Aust., 72: pp. 33-68. Lance, R. T., 1969, The piosphere, sheep track and dung patterns. J. Range Mgmt. 22: pp. 596-400. Lupsroox, N. H., 1961. Stratigraphy of the Murray Basin in South Australia. Geol. Surv. of S. Aust. Bull, 36. Meinic, D. W., 1963. On the Margins of the Good Earth: the Sonth Australian Wheat Frontier 1869-1884. London, 231 p. Norrucorr, K. H., 1965. A Factual Key for the recognition of Australian soils. Second Edition C.S.I.R.O. Aust, Diy. Soils, Divl. Rept. 2/65. O’Driscoty, E. P, D., 1960, The Hydrology of the Murray Basin Province in South Australia. Geol. Surv. of S. Aust. Bull. 35, Osgorn, T, G, B., Woop, J. G., and Parrrince, T. B., 1932. On the growth and reaction to grazing of the perennial saltbush, Atriplex vesicaria—an ecological study of the biotic factor. Proc. Linn. Soc. N.S.W. 60; pp. 392-427. Wootxs, W., 1882. On. the forage plants indigenous in New South Wales. Proc. Linn, Soc, N.S.W. 7: pp. 310-318, Susan BARKER PLATE | EXPLANATION OF PLATES Top left—(a) Gully erosion in the Ki-Ki paddock watercourse. Above—(b) Casuarina cristata suckering from apparently dead parent. Centre left—(c) Young Myoporum platycarpum trees regenerated from seed. Bottom left—(d) View looking west along fence between Well paddock (on right) and George’s paddock. A REVIEW OF THE PRECAMBRIAN AND LOWER PALAEOZOIC TECTONICS OF SOUTH AUSTRALIA BY B. P. THOMSON* Summary Tectonic nomenclature is discussed. Structural features in southern Australia are grouped by means of trend directions into four categories. Arranged roughly in order of decreasing age they are as follow: 1. Northwest. Archaean fold belts of Yilgarn Block are apparently reflected in South Australia by the trends of the continental margin and the north east flank of the Adelaide Geosyncline. 2. Northeast. The Carpentarian and Adelaidean Fraser-Musgrave fold belt and crystalline basement in South Australia e.g. Gawler Craton. 3. Northerly. Adelaide Geosyncline and Torrens Hinge Zone, which is part of a meridional transcontinental structure. 4. Transverse. Adelaidean Musgrave Block overprint trends, repeated in graben development further south during Palaeozoic and Mesozoic. The southern and eastern flank of the Gawler Craton is framed by the Delamerian (Cambro-Ordovician) fold belt. A mirror-image fold belt extending from Office Basin southeast through the Denison Block is probably older (Marinoan-Cambrian). A REVIEW OF THE PRECAMBRIAN AND LOWER PALAEOZOIC TECTONICS OF SOUTH AUSTRALIA by B. P. Tuomson* SUMMARY Tectonic nomenclature is discussed. Structural features in southern Australia are grouped by means of trend directions into four categories. Arranged roughly in order of decreasing age they ure as follow: l. Northwest. Archaean fold belts of Yilgarn Block are apparently reHected in South Australia by the trends of the continental margin and the north east flank of the Adelaide Geosynclinc. ¢ 2. Northeast; The Carpentarian and Adelaidean Fraser-Musyrave fold belt and crystalliné basement in South Anstralia e.g. Gawler Craton. 3. Northerly. Adelaide Geasyncline and Torrens Hinge Zone which is part of a meridional transcontinental structure, 4. Transverse, Adelaidean Musgrave Block overprint trends, repeated in graben development further south during Palaeozoic and Mesozvic. The southern and eastern Aunk of the Gawler Craton is framed by the Delamerian (Cambro-Ordoyician) fold belt, A mirror-image fold belt extending from Office Basin southeast through the Denison Block is probably alder ( Marinoan-Cambrian ). INTRODUCTION This paper presents a review and tectonic interpretation of geological and other relevant data in South Australia and adjoining regions. During the last three years the writer has been a member of the tectonic map Committee of the Geological Society of Australia which is engaged in the compilation of a new 1:5,000,000 scale tectonic map of Australia, This paper discusses some interpretations of crystalline basement and sedimentary cover relationships which haye ariscn Guritis the compilation of the map data for the South Australia region. The writer also takes the opportunity in this paper to revise and amplify tectonic aspects of his contribution to the first three chapters of the “Handbook of South Australia Geology” (Parkin, 1969) in the light of new information from geophysical and gealogical surveys and exploratory drilling. The valuable stratigraphic drilling done by the South Australian Department of Mines in the last two years has meant important adyances in basic geological knowledge, particularly of the poorly known subsurface geology of the central and western areas of the State. In 1969, the Australian Mineral Development Laboratories (AMDEL) in collaboration with the Geological Survey of South Australia began major regional K/Ar radiometric dating projects on the geochronology of the Precambrian base- ment rocks of the Musgrave Block and Gawler Block. Some preliminary dates from these projects have recently clarified several uncertainties in the tectonic interpretation of both areas. TECTONIC CONCEPTS Tectonics (or geotectonics, when applied to structures on a regional scale), is defined by Dennis (1967) as .. , “the science of the structure of the carth’s trust, and of the movements and forces which have produced it. (Derivation: Greek. tekton, a builder; ge earth.) .. ° Supervising Geologist, Regional Surveys Division, Geological Survey of South Australia. Published with the permission of the Director of Mines. Trans. R. Soc. S. Aust. (1970), Vol. 94, 134 B. P. ‘THOMSON From its derivation, tectonics implies an analogy with architecture, and, in fact, tectonic maps have been described as postraying the architecture of the varth's erst by means of symbols, Owing ta the interpretative character of the science, tectonic terms have aoyuited aamerous shades of meaning. An interesting exainple iy the tenon Platform, which is of fundamental importance. lt appears to the writer to have been osed in a slightly different sease io North America to that which has been employed by Soviet geologists in the compilation of tectonic maps of Europe and Asia. Since the concepts involved appear to the author to apply closely to the Precatibrian tectonics of South Australia, they will be discussed in some detail. King (1969), in his authoritative explanatory notes to the new tectonic map of North America, defines a platform as—(p. 86) “.. . That part of a continent which is covered® by flat-lying or gently tilted strata, mwitly sedimentary, which are underlain at yarying depths by basement rocks thut were consolidated during earlier deformations. ..." A part of the craton of the continent®, French “plat- forme”... on p, 21 he adds in reference to basement “consolidated, not only by earlier deformation but in purt by metamorphism and plutonism”, Note that Craton is defined (Dennis, 1967), as “a relatively stable scement of the carth’s crust undergoing no more than epeiroyenic deformation”. King’s definition of platform has been accepted by Dennis (1967), as the English terminology definition of platform in the International Tectonic dictionary. King’s term clearly rafurs to only part of a craton and is restricted fo areas which retain couer*—in fact the emphasis is on the pluttorm deposils (Le, cover), and the areas of plat- form deposits are Separated : according to their age, independently of the age of busemeut. This classification and portrayal of tectonic units serves to emphusize basin development. The usage has been udupted in part by the Australian Tectonic map Com- mitlve for the proposed tectonic map of Australia although a broader concept of platform involving gencralization of the cover rocks is employed. The following description by A, A, Bogdanofl, a recognized world leader in tectonic mapping, also outlines a somewhat broader platform concept... “The East European platform is u typical Precambrian platform (craton). Lts basement is formed of Precambrian metamorphic series and ancient intrusive rocks which outcrop as the Baltic Shield. and Ukrainian massif.t Within the vast territory of the wes! of the platform, known as the Russian plate, the basement surface occurs at considerable depths 1 to.3 km ind locally down to 10 km and is overlain by a thick cover of undislocated, non-metamorphic, predominantly scdimentary tor- mations. The platform cover is composed of Ripliean, Paleovoic. Mesozoic and Genozoie series the sequence of which is most complete within deep depressions of the plate, The prahlem of the exact position of the platform is one of the cardinal and, in many respects, still unsolved problems of the tectonics of the East-Europcan platform, The present outlines of the platform are marked by the positiva ot inarginal parts of fold belts framing the plattorm, The age of the plat- jorm is determined by the time when its folded basement was consolidated,* .. . (Bogdanoff, 1964), Bogdanofl in contrast to King (up cit) here places emphasis on the age of basement rather than of age of cover. The above description has much in common with the tectonic pattern of the Precambrian basement in South Australia, The writer (Thomson, 1965), first upplied the term Gawler Platform to the area which included the Gawler ® Author's italivs. : p + Author's italics, It is assumed here that platform lasemeat. shielil and inassit ae port of the eraten. PRECAMBHIAN AND LOWER PALAEOZOI TRCTONICS INS. AUST, 195 Critonic Nucleus of Sprigg (Dickinson and Sprigg 1953, p. 424) and its extension in the subsurface, Subsequently the writer (in Parkin 1969, p. 25), lias extended the term to include part of the continental shelf areas to the south and west, Although this usage of platform may incorporate basement areas of similar time range, it is too broad to agree with international nomenclature, therefore ta avoid confusion with anticipated nomenclature of the forthcoming Australian map, it is proposed that the term Gawler Craton® he adopted in liew of Gawler Plat- forns*, Craton is used in the sense of Dennis (ibid). This usage has the advantage of applying a specific geological time interval (ie. post-Carpentarian)) to a structural feature which in part ix basement to some areas of a more extensive “Central Australian Platform’. The Gawler Craton includes Gawler Block, Yorke Peninsula basement and shelf areas, Mt. Woods and Wallabying Inliers, Stuart Shelf, southern margin of Olficer Basin, portion of Eucla Basin, offshore areas in the Great Australian Bight and Eyre Peniusula and northern Kangaroo Island, Details of the gcology of the Craton will he given later in this paper which is largely concerned with basement tectonics. The term “Shield”, although strictly applying to individual extensive ont- eropping areas of basement rock { Dennis, 1967), has not been used in a strict tectonic sense in the case of “the Australian Shield”. This expression has loosely come to mean that part of the continent containing crystalline Precambrian erustal rocks, Note here that Doyle et al. (1968), discussing seismicity, considers it quite likely that Precambrian rocks extend under eastern Australia as part of the “pranitic” layer detected by seismic methods. Confusion in tectonic terminology and nomenclature also arises from changes with time of spatial relationships between parts of the crust. As an cxample, the Precambrian basernent aves of the Gawler Craton correspond ¢losely with those of the Preeambrian Willyarna Block to the east (Compston and Arviens, 1968). Tt is reasonable to assume that the two tectonic units once formed part of an older larger craton The writer believes that the development of the Adelaide Geusyncline and of a subsequent Palaeozoic fold belt destroyed the cratonie character of the castern region of the older craton which has sinee retained a mobile character distinguishing it from the Gawler Craton pruper. An atalngoos problem is in the naming of sedimentary basins which belong lo separate tectonic aud depositional cycles but which are in part superimposed on each gather, Wopfner (19692) has employed » separate name for cach basin associated with a specific cycle in the Phanerozoic basins of South Australia, Where informating is available his system will be followed in this paper. THE PRECAMBRIAN BASEMENT (1) Pold belt trends in Southern. Australia Crystalline basement structures have played a fimdamental role in the development and tectonic histery of Phanerozoic sedimentary basins ( Wopfer, 19694) and localization of metallagenetic provinces in South Australia (Thomson, 1965). As a consequence, the fullest possible study of the basement is justified if lang range assessment of future mineral resources is to be seriously attcurpted. The setting of the South Australian region in the Anstrulian Precambrian crystalline basement framework is illustrated by Fig, 1. This figure has been yreatly simplified from the current draft of the 1:5,000,000 tectonic map af Australia in preparation by the Geological Society of Australia. Structural trends are emphasized, fault structures have been omitted for clarity. The nomenclature ® Author's italics, 196 #, P, THOMSON of Daniels and Horwitz (1969), has been adopted for the tectonic units in west- em Australia. Radiometric age limits have béen adopted largely from Compston and Arriens (1968), Tie basement trend lines represent the traces of fold-belts that have generally viidergone more than one phase of metamorphism and deformation eg.. in the Willyarna Block (Binns. 1964; Talbot, 1967, Vernon, 1969). The structural over- printing leads to patterns in rock Jayeriny that, although hewilderingly complex in detail, are believed by the writer to be tectonicaliy meaninghil even when considered on the grossly generalized scale of Fig. 1. (2) Northwest trending features The northwest trending Archaean fold belts of the Yilgam Block have not lo date been recognized as such in the internal fold structures of the basement in South Australia. The northwesterly trending outline of the Gawler Block however, reflects the significant major basement features within the continental shell to the west described by Smith and Kamerling (1969). The first of these is the con- tinuation to the northwest of the Cygnet Fault from Kangaroo Island. This steuctucc forms the seaward boundary of shallow Precambrian basement. Parallel to this boundary and farther southwest in the Duutroon Basin a deeper structure is outlined by a chain of basement ridges. This chain is in alignment with the southwestern margin of the Gawler Craton. At the head of the Bight the sarc zone is marked by an intracratonic trough in the basement cover (Vig. 3). Further to the northwest within western Australia, a marked change in trend of the deep trough of the Officer Basin around the Musgrave Block is located in the same zone. Still further west, Archatan structures in Yilgarn Block basement appear to contral fold trends tn the Bangemall Basin sediments of probable Adelaidean age. The northeastern flank of the Gawler Craton is also the site of a swarm of shallow northwest trending positive veromagnetie anomalies which imay represent basic dykes (Webl aml Woyzbun, 1967, see appendix)® such as secur in the Musgrave Block. Vhe Adelaide Geosyncline and the alignment of the Willyama, Mount Painter and Denison Blocks are an expression of a bigger regional feature incorporating the MacDonald Shear Zone, Norwest Fault, Muloorinna gravity ridge, Lake Fyre and Lake Blanche Faults. To the southeast of the State the prolongation of the Padthaway Ridge marks u major north- westerly swing in trend of the northern margin of the deep Mesozoic-Tertiary Otway Basin which is very similar in structural style to the interpreted pattern of the Duntroon Basin and likewise may have a metamorphiv Palaeozoic base- meal (Wopiner, in Parkin 1969, p. 161). South of the Otway Basin, Precambrian rocks reappear on the same trend itv King tsland and Western ‘Tasmania where they are probably afteeted by late Precambrian folding and plutonism (Compston and Arriens, 1968), Although mast of the northwest trending structures described are evident as a result of Phanerozoic tectonism, it is interesting to speculate that they may reflect funda- mental northwest trending structurul features that were established in the crust in Archaean times. The writer has already proposed, from stratigraphic and structura! evidence (Parkin, 1969, p. 28), that a continental Archaean crustal basement underlay South Australia in Lower Proterozoic time, © Por the purpnses of the following discussion use has been made of a number of unpub shed Reports, The full titles of these are given ay an appendix to the References at the end of the paper, This is indicated in the text by inclusion of (see Appendix) at each such notntion, Sy SINS. AUST. ‘ 4 PRECAMTIMTAN AND LOWER PALABOZOLG TECTONIC SONS LYINS JO YO waninap TUTIN] Words Wet eh wih ae —— 49P19g, DIS WE poriny Unas, POTTS TT Sa sadp alsGq) SH OWOUD DisUBowW Jnsui] a BP jus ZA a Om mnnmn= sin) SEUIY 4a ta Stump UMtog Ato) udu pag SAWIWOUN OOF OOF = NOM a 7 fe AunasWels MOLSON, Nh idsuspog %, SIUW 00E LIWE evewesog : = ° . \ MOOG Ls ea F a HOMSI¥dNI JAVTI YY AIDE ADEL NOLINEWW AA yoota?! =j— LU FRE TT NSIHLION 2 SS NOSIN3Q a —— . —_— sBuirdg anny me ONES PSY oats SSSSAL AUN'ON at Ba TT Auaidig unis a) Buipisy aaay pry ome “e" HOah 1O GW ‘abo 4 dajosy UalLamOD MAY OLSArry cin Yoliqdoy ucau ay %, % Oat $3813aWOr|4 ns Oo Sauw TOT POO O Alia pha) Qo BAS +0 ‘PID. WHauaarOg SNUOOA YOUD\UAdIE) aoibsn Wy —I3s5 y ~~ Ole u) SB 1 WHY IOMO aw Og )s0q JONIHIAIY JOON sey jo doy si veyoey DOO DUNS’, ee Hobs vena) OLel vorMUy | gE SOE) LOUD adINT 307 JONIAQUd waSvad ANVETY 2 490718 JLSHIVUNLYN ' “WOOL 2. eS N Did WWHLUGN ¥ SVAN ‘ANAOISVD Si a “#wOoLT Pw a ANS ; is NISWS TIVWIONVE SS FONIADH \h\ >, NOSHal Yd “ROT os F Fett RSs SSN ve Wd01e WavETaH 198 R. P. THOMSON (3) Northeast trending features and the Gawler Craton Boundary Problem, (1) Tite FrAsen-Muserave Foro Bett The: Precambrian geology of the eastern part of the Albany-Fraser Province flanking the Archacan Yilgarn Block has been outlined by Wilson (1952, 19695, Morgan et al, (1968), wud Doepel (1969), ‘The latter believe the encisses on the southvast coast to be of Archacan age, although this fold belt is at right angles tu the known Archaean fold belts in the ¥ilgarn Block. Shallow crystalline basement eontinnes, under the Eucla Basin (Peers and Trendall, 1968), Ludbrook in (Parkin, 1964, p. 195), and under the Great Australian Bight (Smith and Kamer- Tiny, 1969) dnd. deepens to the northeast under the Officer Basin, reappearing at the surface in the southern part of the Musgrave Block which has a dominant northeast trent (Tharnsen, in Parkin (1989), p. 24, 34-45). The central and northern parts of the Block however have a complex pattern in which sorth- casterly trends are Sargely obscured by other cross-cntting structures, Within the Arunta Block to the north, in the Alice Springs region, northerly to northeast fold trends are preserved within strong east-west stiuctures. These northerly trenecls are considered to be relies of folding which was associated with the Arumtu Orogeny, prior to development of the Amadeus Basin (Wilson, 1953; Wilson et al, 1960; Wells, 1969). Further support for the interpretation that & major trans- continental structural feature exists, is provided by the striking alignment of the southern limits of outcrop of the Mt. Isa-Cloncurry and Georgelown Precambrian basement inliers in Queensland with the eastern limits of the Arunta and Mus- wruve Blocks and the Fraser Range area, The writer believes that in the Fraser- Musurave Nanges region this alignment represents 4 complex Precambrian fold melt associated with the Musgrayian orogenic cycle (Parkin, 1968, p. 43.) believed to haye heen active between 1400 and about 1100 my, The foldbelt contains some older crystalline basement rock units that suggest that the Musgravian cycle has overprinted on an older Carpentarian basement. li the Musgrave Block wid the Albany—Fraser Range Province, granites with radiometric ages bebveen L100 and 1200 m.y. have bern recorded (Turek and Stephenson, 1966; Compston and Arriens, 1968). Arriens and Tjambert (1969) obtained a 1328 + 12 m.y. isochron for the granulite facies rocks in the Fraser Range and a less distinct 1380 + 120 my. isochron for the granulite faeles rocks of the Musgrave Ranges, Adjacent gneisses in both areas gave possible ages from 1660 to 1900 m.y, in the Fraser Range area and 1400 to 1650 m.y., in the Mus- gruve Range, Arriens and Lambert (op. cit) associate the granulite isochrons with periods of rapid uplift and favour a geosynclinal and volcanic origi far the yramuilite facies rocks, The writer on the other hand. considers that the granulites in part, at least, represent sediments thal were deposited during the Lower Proterozoic and were prubably first incorporated in a fold belt in the Carpentarian ( 18tl0- 1600 my.) (Thomson, in Parkin, 1969, p, 43), According to Ariens and lambert (ibid, p. 385) such an interpretation, in order to explain the low Sv87/Sr86 initial ratios oF the granulite rocks, would require selective expulsion of Srs7 during metamorphism, A futher complicating Factor that should be noted is that heth sampled areas of granulite rocks adjoin profound regional fault zones which must represent zones of immense, and possibly oscillating vertical movements during the Prewambrian with consequent cffects on possible “cooling dates” { Moorbath, 1967) of these rocks and opportunities for isotopic fractionation and diffusion. Lhe isotopic evidence where stratigraphic eviderwe is not available. nevertheless is al great value in providing the only method for distinguishing crystalline rocks of the Fraser-Musgrave Fold belt from those of the Gawler PRECAMBRIAN AND LOWER PALALOZOIC TECTONICS IN & AUST. 194 Craton, At present the minimum age of the Gawler Craton platenic and meta- morphic racks is assumed to coincide with the L400. my. Adclaidean—Carpentarian time boundary, Webb 770) (sce appendix) has determined K/Ar radiometric ages of biotite and hornblende from granitic rueks in the Musgrave Block and Gawler Craton. These preliminary results show that Gawler Crtun gneissic basement (i.e, ages in excess of 1400 m,y,) persists in the subsurface to at least as Ear north as latitude 28°S, whereas the granites in the eastern end of the Musgrave Blook have been affected subsequent to emplacement, pussibly at ca. 1100 muy. by 2 metamorphic event at probably about 1000 my, This last event corresponds to the Winznyan Phase of the Musgravian Orogeny proposed by the writer (in Parkin, £969. p. 44-45). The northwestern boundary of the Gawler Craton shown on Figure 1 was interpreted as coinciding in depth with the Cambro-Ordoyician and Adelaidean hinge zone located by Wopfner (19698, Fig, Ib) in the snb- surface of the eastern Officer Basin. This boundary has heen extrapolated to the southwest following approximately the 2 km acromagnetie basement contour derived from an interpretation by Adastra Elunting et el. (1965) (sce appendix) (sec Fig. 6 this paper). Below the Eucla Basin in Western Australia the boundary is assumed to pass between Eyre No. 1 and Madura No. 1 bores where Togram (1967) has recorded a thickening in Cretaccous cover, It is suspected ly the writer thut this feature may be controlled by a northeast trending basement structure, In the western area of the Great Australian Bight, the boundary would cross the continental shelf eastwards of the Archipelago of the Recherche where Morgan et al. (op. cit.) record that a granite, considered hy them to be the equivalent of the 100 my. Albany Granite (‘Turek and Stephenson, 1966), has traded an older layered sequence. Following this intrusive event the sequence was folded inte a broad anticlinorium, (ji) Taw Gawrern Craton (a) Granulites and structural relationships Granulite-facies rocks may not be confined to the Fraser-Musgraye Fold belt in the subsurface, as recent mapping and petrographic examination of exploratory and stratigraphic bores to basement has established that a major zone of granulitetacies cocks, not recorded by Wilsun (1969), extends apparently in a northeasterly direction across the northern end of the Gawler Block. The zone is also represented by granulites in the small inlicr of Mt. Woody further cast and, in the subsurface to the north, in Wallira No. 2 bare (Fig. 2), The age of the granulite metamorphism in this arca has not yel been dated, however, Webb (1970) (see appendix) usiny biotites fram wneiss. of apparently lower metamorphic grades, in Walliru No. 1 and Mt. Furner No. 1 bores (Fig. 2) obtained K/Ar dates of 1460 xy, and 1432 to 1439 my. respectively, Wallira No. 1 bore oveurs near a gramulite area and Mt, Furner No. 1 bore is located uppar- ently ta the north of the zone, Since the biotites would be sensitive ta past- granulite metamorphic events, the true granulite ages are interpreted us possibly considerably greater than the indicated biotite ages and cocval, with the meta- morphism of the ca. 1800 m.y, Kimban phase of tectonism of Eyre Peninsula to the south. The possibility that the granulite-facies rocks of the Craton extend below cover ta the northwest to adjoin the zone of granulite metamorphism of the Fraser-Musgrave Fold belt, raises again the question that some areas of regional gramulite metamorphism in the Musgrave Block may be of considerably freater age than the 1380 m.y. age proposed by Arriens and Lambert (1969) in the Ernabella area, The northwestern und southeastern position of the Gawler So £2 a (7 AMMAROODINNA — AT WATER «= EOORBER PEDY ee a ve (ALLIRA TROUGH ig tae € yes we ye gtanulite 7500. fs aa = —“"< a) a No.1 xj (ol SeWALLIRA Ne SER MARALING Ser r vet r SEES S. ~. SV SS 5 AN SS SS See LOCKSS eae SS ‘ SERS : AX ~ \ me \ LEGEND Sc) Gawler Range Yaleanics —500—gosement contauts, metres ® Pores lo Basement Dapth in ref. MSA. (Milfan Fe?) metres rel M.S a 4 Taroola Bede 5 Precomln jan Basenmenr ——500-fovemen! farmlings, metres *, linear moanefic onomolier 7s with tolidtica trends teh MSL. RSS Granulile Fees Werhary), MiMesozaic, PlPgloegoicl, ClCumbrian), @ClPrecambrion’ SCALE MILES O o 40 60 80 100 MILES KILOMETRES © 20 4 bo 8680) «(100 KILOMETRES Dwecew 7o—5uC BP Thomsen 170 SA Dect ot Mew Fig. 3. Basement Sirtictures; Northern Gawler Craton, PRECAMBRIAN AND LOWER PALAEOZOIC TECTONICS IN S. AUST. 201 Block (the major outcropping part of the Gawler Craton) is made up of tbe Cleye Metumorphics, which the writer correlates with part af the Lower Proferc- zoic Mt. Bruce Supergroup (Daniels, 1966) of the Hamersley Basin in Western Australia. The Mt. Bruce Supergroup sediments are considered to have a time range of fram 2200 to 1950 m.y. (Compston and Arriens, 1968). The Cleve Metamorphics contain two major iron formations which provide important keys to regional structures. Whitten (1966) (sce a pendix) demon- strated, from mapping and study of aeromaynetics, that 2 nor easterly trending auticlinoriam is present in the Wilgena—-Mt. Christie area (Figs. 2 and 5) an that a major synclinorium occupies a large purt of the southern Eyre Peninsula The western limb of the synclinorium extends northwards along the west coast to Elliston and from there strikes northeasterly to Warramboo, The eastern limb follows the trend of the Lincoln and Cleye Uplands and then contiunes north- wards through the Middleback Ranges. Subsequent regional mapping (see Fiz. 7, Parkin 1969} shaws that north of Cleve the synclinorium trends to the northwest, it consequently has a sygmoidal outline in plan, indicating that it has undergone more than one period of defwr- mation. The overall trend of the synclinorium however, rémains northeasterly, ‘the presumed anticlinorial area north of Elliston fs poorly exposed and it is feasible that it may represent the metamorphosed equivalent of Archaea base- meut, No radiometric dates yre available from the area. Whitten (op. cit.) interpreted the iron formations revealed by acromagnetics and drilling in nerthern Yorke Peninsula as occupying an east-facing anticlinorial limb structure, striking north-nortinvest. A consequence of this interpretativn is that the lower part af the Speneey Gull area is largely oceupied by i north-northeasterly trending anti- clinorium, This is supported by the northwesterly strike of bascment foliation in the Sir Joseph Banks group of islands aud the west-northwesterly strike of gneiss in southern Yorke Peninsula. In Gulf St. Vincent, the east-tacing anticlinorial limh is probably marked by the meridionally-trending decp Orontes basement bluck from the head of the Gulf to the foot of Fleurieu Peninsula from where basement anticlinorial inliers reveal northeasterly trending infra-basement structures through the Mt. Lotly Ranges. The character of the basement in the subsurface to the north has already been mentioned above (Fig. 2). The isolated outcrop of basement at Ammaroodina Hill (Krieg, 1970), south of the Musgrave Block, has been assigned to the Fraser-Musgrave Fold belt since it uppears to haye partici- pated in Palaeozoic folding of nearby Adclaidean and Paleoznic sediments, Seismic and gravity investigations and stratigraphic drilling show that the northern limit of the Gawler Block is marked by narrow basement troughs which ave frequently fault bounded. Isolated outcrops of uranite gneiss along the north- west Hank of the Gawler Block have been recently mapped by helicopter and northeast trending foliations established. (A. F_ Williams pers, comm. ) (b) The Mallabie Depression Basement cores and cuttings from selected bores in the Encla Basin are bein re-xamined and Fig. 3a and 3h was drawn after sludy of available data, The huried structure, revealed by drilling and geophysics records important events in the histary of the Guwler Craton. The section studied includes the Mallabie No. 1 bore which was drilled for Outhuck Oil Ca. (Scott, 1969) (see appendix), ta explore the trough revealed by a Department of Mines seisinic velraction survey (Kendall, 1965) (see appendix). The basement profile shown on the section has been adjusted ta follow xpyroximately the shape suggested by Kendall's high sped refraction contours, The seismic results were complex in the western part of the trough where a refractor with 18,500 ft/sec (5°6 lan /sec) to 202 B, B. THOMSON a3 | HURSHES No.3 Watson Qo HUGHES No.2 Hughes | NULLARBOR No.8 ALBALA KAROO (YANGOONABBIE! a, Se es 6 sg 5 ~GUINEWARRA GREAT AUSTRALLY pp ie LOCALITY PLAN GUINEWA RRA | NULLARBOR No B (YANGGGNABE NULLARBOR No 6 Pidinga Rock Hoe ALBALA KAROD | MALLABIE Noe] NULLARBOR No? Wot 2400 aboe ? REFERENCE Hezemen' contour in km. below M.5.L,- ~~ .-—--1-—~__ SCALE 50 50 100 «150.200. MILES Faults observed inferced Palasozele metomoraham— —~—____—___ at le MILES 50 100 150 200 250 300 — — Polocozcic granite Precambriar crystalline bosémert KILOMETRES 70—b5a ' Cowmlas by OF. Thama4on 1970 5A Pep on) Mines Fig. 5, Precambrian basement contours, form lines and other structural featurcs in South Australia. PRECAMBRIAN ANID LOWER PALALOZOIC TECTONICS LN 5. AUST. aug To the southeast the Gceosyncline appears to be flanked by a Cambro- Ordovician fold belt extending to the north east. The Willyama Block and the shallow crystalline busement east of the Palacozoic Arrowie Basin (Wopfnevr, 1969a) forms the castern margin. The northern margin is formed by the Muloo- tinna Ridge extending between the Mount Painter and Denison Blocks. To facilitate the study of the Geosyncline and related features in South Australia the wriler has prepared a basement contour map (Fig. 5) from all data available to him (Appendix 1), The map is largely 2 compilation of aeromagnetic basement interpretations by the Bureau of Mineral Resources and petroleum exploration companies and, where possible, it incorporates seismic and stratigraphic drilling data (e.g. Milton, 1970) (see appendix}, On the whole the map probably should be veterred to as a basement form-line map. In poorly known areas it is likely that basement depths ure probably more shallow than shown, The basement depths in the central zone of the geosyncline are very conjectural as the effect of Lower Palaeozoic metamorphism has dominated the acromagnetic record. The iaximum basement depths i excess of 10 kn have been estimated from: struti- graphic thicknesses, Th places it has not been possible to allow for the effect of decollement which has occurred. South of the Willyama Block the presence of the Palacozoic Anabama granite and marked regional metamorphism has ¢on- verted the geosynclinal sediments to new crystalline basement. A north-south basement fault probably extends from the Olary area (below the Frome Ermbay- ment) to the Mount Pamter Block and, together with associated Palaeozoic granites (Coats and Blissett, 1970), is in aligment with the western limit of the Anabama Granite. South of the Anabama Granite area, north trending basement faults appear te intuence the aeromagnetic basement contours. (b) Duration of the Adelaide Geosyncline The writer has maintained (Thomson, 1966) that (he geosyncline con- tains sediments extending back to about 1400 my. The consequent concept of an Adelgidean System is fundamental to the tine otra tierapiig subdivision of the Australian Precambrian which was proposed by Duun et al, (1966). Subse- quent investigations, such us the stvatigraphie drilling of the Mallabie depression described above and in the Roopena area (Fig. 6) on the vastern flank of the Gawler Craton, support this concept. A strong argument that the conventional role of biostratigraphy may yet be employed for world-wide eorrclation in the Precambrian is advanced by Glaessner et al. (1969) who demonstrate that the évidence of stromatolites in the Geosyncline supports a middle Riphesm age (1350 = 50 to 950 + 50 m.y.) for the Callanna Beds either alate, or muluding the overlying Burra Group. For a recent summary of the stratigraphic record of the Geosyncline the reader is referred to Parkin (1969, Chapter 2). The effect of the Musgravian orogenic event on the Adelaidean sequence in the Geosyncline has yet to be elucidated. The writer has assumed in (Parkin, 1969, p. 52) that 2 break in sequence between the Upper and Lower Callanna Beds may have resulted from this event. The duration of this assumed regional hiatus may be resolved by close study of the stratigraphy and genchronology of the Duff Creck Beds along the north-east side of the Gawler Craton in the vicinity of the Denison Block and further south in the Willouran Ranges area, (c) Palaeogeography The earliest known event was probably the development of a sheet of basin sediments (mainly continental), associated with basic volcanics, extending from the Mallabie Deptession eastwards ta the north of the Willyama Block, The sequence probably passed into a marine fuvies to the north for example, marginal su B, P. THOMSON to the Painter Block. The source area to the south was the basement established in the Carpentarian Wartakan tectonism. The hasin was probably ferminated to the west by the Fraser-Musgrave fold belt. Vhe orientation of the original basin is obscure, In later Willouran and in Torrensian time the Upper Calfanna Beds and Burra Group were deposited in a deep trough bounded to the west by the Torrens Hinge Zone. and show that the Adelaide Geosyncline was a downwarped structure in elder cratonic basement. The Gawler Craton area to the west became a mnujur source grea for the sediments. Subsequent Sturtian and Marinoan troughs in the Geosyucline appear to have had their thickest deyelopments east of |his Late Willouran-Terrensian trough (Thomson, in Parkin, 1969). The palaco- geographic relationship of the Torrowangee Group (Rose and Brunker, 1969), on the eastern flank of the Willyama Block. with the Adelaide Geosyncline has not yet been resolved, The Torrowangee sequenees slow obvious close lithologie correlation with the Adelaidean of South Australia (Thomson, 1969). The Group probably occupied a separate easteny basin that had intermiltent counvction with the Geosyncline, (ii) NortHern Basins Basement form-lines and scunty Dore dali indicate that remnants of Adclaidean cover form the floor of the Boorthanna Trough af the mid-Palacozoic Arckaringa Basin (Wopfner, 19690) and extend northwards below the floor of the Palaeazaiv Pedirka Basin (Wopfner, op. cit.). A saddle structure connecting the Musgrave Block and the Denison Block appears lo separate the basins. The Muloorinna Ridge forms the eastern flank of the basin chain and apparently connects with the McDills Anticline (Stewart, 1967) in the Northern Territory. The truce of tre basin chain farther north is obscure; it may die out within the saddle-shapedl depression shown in the “McDills Gravity Platform” (Stewart, op. cit. Fie. 2). This platform prabably represents Musgraye Block bascment. Lt is very likely, considering the stromatolite evidence of Glaéssner ef al. (1969), that the Adelaidean (?Torrensiun) sediments which formed the Hoor af the Officer Basin and Amadeus Basin were deposited after the ?Willouran Duff Creek Beds. ‘The palacugcography of the areas of Willouran sedimentation remains to be resolved, (iii) Mayor Grorecronic Staucrorrs The Torreus Hinge Zone forms the western margin of a network of conti- nental fractures (ending west of north, The network covers a wide belt ta the northeast and incorporates the Tibooburra Ridge of Rose and Brunker (1969), and extends northwards to the Ammhem Land and Carponturia areas of northern Australia where it has apparently affected Carpentarian sedimentation. Most of the major known Precambrian base metal deposits (e.g., Mount Isa and Broken Hill) are incorporated in this belt which is consequently of profound imetallo- genetic significance. The southern prolongation is highly speculative, bul, gravity. acromagnetic features and the continental shelf north of tle Gambier suh-hasin of the Otway Basin suggest that the network has been active since the Canhre Ordovician (Delamerian) Orogeny. It is likely that the apparent displacement of the mid-ocean ridge between Australia ed Antarctica which was interpreted by Heirtzler ct al, (1968) from rather sparse magnetic data, is related to the sume network of faults. (5) Transverse Trending Structures (i) Gruxrmar. Numerous important features trending castavest or west-northwest truncate carlier established patterns of folding, Some of these featnres are graben or half PRECAMBRIAN AND LOWER PALAEQOZOIC TECTONICS IN &. AUST, 21 LEGEND Le | Grovel, alluviin “Bep™| PANDURRA FORMATION ee “J Sandifers \ecr’] ROOPENA voLcaNics VI] Basel) ADELAIDEAN — QUATERNAR DACKY POINT TORMATION Ssole and sardstany Spy’ | GAWLER RANGE VOLCANIC , i = ef /, ~. e 1 ' 1 Sef > ' im Tt : | 5 ; | ae ‘ i Z = 1 at = ) { rq ' t “ | of i We Wy j Y) ay Hi, yy | = Ey € & S ao < a } le on imenis. resting urcentormably o ler Kocsement of TORRE SIAN TRAMSGRESKIVE FACIFS [Heayitroe Quariziteand Equiva alder by Indcusive geaniles of older basement {de tellotion trends KULGERAM GRANITIC ROCKS _ dca 97 bul vm RASIC DYKES. GILES: COMMLEK Valconics Fig. 7. Generalized Geological map of Musgrave Block. Si 6. 1. THOMSON rocks (Wells, 1968: Ranford, 1968), The writer believes that Us is the same assemblage that oceurs south of the Amadeus Basin between the Petermann Ranges and the Warburton Ranges and, execpt for the Townsend Quartzite équivalent, represents the Bentley Supergroup of Danicls (1989) (see sppenilix). The writer also believes that farther to the east, the possible metamorphic: equiva- lents of the Bentley Supergroup are the Olia Gneiss and the (?) infolded Dean Quurtzite of Forman (1966). The metamorphic equivalents in South Australia we probably the schists and gneisses north of the Woodroffe Thrust which arc wssociated with granites of the Kulgeran phase and the Winanyan oyerthrusling fram the south by gneisses and granulites of the older Musgravc-Mann Meta- morphies. This interpretation explains the contradictory gravity and aeromagnetic patterns in the Musgrave Block and southern Amadcus Basin (Stewart. 1967). The identification of the Heavitree Quartzite equivalent in the southern Amutteus Basin remains a major problem. It is probable that it is represented in relatively shallow basins on the metamorphic basement just described. The west- northwest trending Ayers Rock—Mount Olga depression, the east-west Moorilyana Graben and its relic extension to the westuinthwvask (south of the Mann Fault) and the Cobb Depression near Giles in Western Australia are thought by the writer to have developed at the close of the Winanyan Phase and to be occupicd in South Australia, at least, by Adelaidean sediments probably of Tarrensian age. MARINOAN AND LOWER PALAEOZOIC TECTONISM (1) Ceneral Sedimentation in the Adelaide Geosyneline appears to have been terminated in the Middle Cambrian by the carliest tectonism of the Delamerian pa! (Changers in Parkin, 1969), By early Ordovician the Orogeny had incorporatec the Geosyncline, Willyama Block and Kanmantoo Trough into a fold belt with importunt metallogenetic associations. Prior to the Delamerian an earlier orogenic event affected the eastern margin of the Gawler Craton, Olficer Basin and Denison Block regions, It was suggested by Wopfner (1909) that the event wis late Marinoan in age and was associated with granites intruding Adelaidean sediments in the Denison Block region. This imterpretation is finding support from preliminary K/Ar ages for the granite obtained by Webb (1970) {sec appendix) which indicate an early Cambrian age. Sedimentation appears to have resumed in the Officer Basin during early Ordovician while the Delamerian Orogeny was. in progress in the Adelaide Geasyucline and further south and east, (3) Tectonism and Basin Developments ast of the Musgrave Block the known record af Proterozoic (late Mariniean ) sedimentation in the northern basins is sparse fe.g.. Mount Crispe No. 1 well), tt is probable that folding had already commenced in curly Cambrian ime in (he vane connecting the Denison Block with the southeastern margin of the Musgrave Block and, in the Hoor of the Olfiver Basin where Cambro-Ordovician sediments were later deposited, This event is here named the Indulkanan Fold- ing. A hiatus in the late Marinoan sedimentary cover of the castern flank of the Gawler Craton suggests that in this region there was a Marinoan-Lower Cam- brian epeirogenic movement which was probably synchronous with the mild Duttonian Folding in the southern part of the Geosyncline, By the close of the Murinoan, or earliest Cambrian, widespread regression bad probably occurred over much of the Geosynelme. By contrast, this was followed in the Lower Cambrian by a widespread transgression associated with subsidenve ot the Geo- PRECAMBRIAN AND LOWER PALABOZOIG TECTONICS IN S. AUST. 215 syanline and marginal areas of the Craton. Wopfner (19692) has demonstrated that positive movements of the Willyama Block took place at this time. According to Wopfner, wear the end of the Lower Cambrian the Cireuim—Denison Ara formed a locus of areas of negative movements with com ensating positive move- ments of the Gawler Craton and Willyama Blocks, Subsidence of the Arrowie and Stansbury Basins also occurred at this time. The most intense moyements touk place in the Kanmuntoo Trough (Thomson, in Parkin, 1969}, in an are which roughly formed a mirror image of the Cirerm-Denison Arc, The Trough truncated the southwestern Hank of the Gawler Craton and extended trth- easterly to the Willyama Mlock. This eastern sector of the Trough obliquely irunitates the Adelaide Geosyncline, The central part of the Trough, adjacent to the southem extremity of the Cratm was the site of major differential yertical movements an basement faull blocks. These vertical movements haye been named the Cussinian Uplife (to the north) and the Waitpingan Subsidence in the floor of the Yrough (Thomson, in Parkin 1969, pp. 99-101). The resultant erosional and depositional rates mitst have been extremely rapid as about 50,000 feet of poorly sorted elastics were deposited in the Trough hefore the end of the Lower Cambrian, Sedimentation in the Trough probably eontinued into the Middle Cambrian, These later sediments were removed by subsequent erosion, Positive movements connected the area at Cassinian Uplift with the Willyama Block. In the north, sedimentation im the Citcurn—Denison Arc commenced with a new transgression (Wopfner, 1969a) in the Ordovician and sedimentation probably continued until almost the Upper Ordovician when it was terminated by folding. (3) Development of the Svuthern and Northern Foldbelts After Middle Cambrian there was a hiatus in the sedimentary record in the Adelaide Geosyncline due to folding, The subsequent metamorphism of the fold belt was complex, In the Mount Lofty Range area of the fold belt Offler and Fleming (1963), have detucted three phases of folding. Extensive faulting tuok place, pene-contemporaneausly with plutonism and metamorphism. The region of the southern are was converted inte a crystalline basement massit by the carly Ordovician, as indicated by isotopic ages of granites from Victor Harbour, Palmer and Anubama, Webb (1970) (see appendix) has recently established a similar age for granite from Kingston, thus demonstrating that the plutonisrn was wide- spread, The Willyama Block was folded and sheared during the Delamerian Orogeny and some pegmatile and minor granite intrusion probably occurred there at this time. The Block appears to have acted as a “hinge” area between the northern and southern fold belt ares. The history of the northern fold belt arc is, at present, paorly known, It is likely that the basement wlong the Muloo- rinnt Ridge was tolded and intruded by late Precambrian or early Cambrian granite and Luter was upthrust to the south and southwest uwlone an arcuate system of sleep reverse faults, Northwest of the Mount Painter Block it is possilile that this feature truncated a former northerly extension of the Adelaide Geo- syneline. The geochronology of the apparently post-Adclaidcan granites in the Mount Painter Block has yet to be adequately invesligated. Current K/Ar evidence suggests that the Dclamerian tolding may not have aflected the Mus- gnive Block or Officer Basin area, The fold helt probably extended north of the Denison Block to connect with the MecDills Antictine (Stewart, 1969). The crystalline basernent floor of the Geosyneline was apparcuthy acHyated both mechanically and thermally at this time and namerous sinmall base-metal ore bodies were emplaced in the Adelaidean and Cambrian rocks of the Geosyneline. 216 GAWLER CRATON TALL SLES LI LSD CELE IILD SM ot Terran sme WILLYAMA BLOCK CAMBRIAN MT. PAINTER B. P. THOMSON DENISON MUSGRAVE BLOCK SEE ees IAAT EPL sSttS FIT IFLA 7 LIE: Ai ‘Mat inobn Ce “yy AAAAAABAAABAAAAAAASAA Ze LE Mild Teclonism pee vyrureyyVy YY. LEE AAMAAAAA aheaa TU ete Reet LT, ADELAIDEAN Mild Techonter 4 He weeestay y Wiler gee Yee ZEEAMNN NS em +F A ae WARTARAN Mo z PHASE qehand: ad ++ wi db Peamarie + tYnbaee TN ya ROLE Lie aMOkPH [SA tbe <> fe" eel oye BP, Thomson 1970 thy, Seiibd binge ha es Wiech on PPP LE OE 4 i ee TECTONIC CYCLE | 2) = | a - a = 60 80 = w z = Fi a ha UM ka ye RAINFALL 25 (44°C) 40 L— m 4. 40(102mm.) MONTHS Fig. 8. Mean monthly rainfall and maximum and minimum screen tem- ere at Eucla. Data from Australia; Bureau of Meteorology (19586). Northcote et al. 1968). However, there are also large areas of dunes (Fig. 2) of various types and ages. The young dunes nearest the coast were of calcareous beach sand, except at Twilight Cove, wherc the sand is white and siliceous with a very small shell content. The beach sands further west, past Point Culver, appear to be siliceous also (Northcote ef al. 1967). There are at least two types of older dunes. Deep calcareous sandy types (Table 1 Site 7) were the only ones seen in the eastern Roe Plain (Sites 5 & 7), while dunes of siliceous sand over aeolian calcarenite (Table I Site 11) were the only ones seen in the west (Sites 8, 9 and 11). Much more work is necessary before the distribution of each type can be mapped, TABLE 1 Description of two dune soils in the stucly area. Site 7 Depth (em) Colour Description 0-13 pale brown Caleareous loamy sand with small CaCO, nodules 13-38 pink : Caleareous loamy sand with small CaCO, nodules 38-140 pink Caleareous loamy sand with more frequent CaCO, nodules 140-152 very pale brown Caleareous sand with CaCO, nodules and shell fragments Site 12 Depth (em) Colour Description (1-10 pale brown Sand 10-51 very pale brown Sand 51-66 yellow Sand 66— Sheet limestone 230 Ri. F. PARSONS BIOTIC INFLUENCES The introduced rabbit (Oryctolagus cuniculus) is the most common grazing mammal in the area; in 1947, thirty-five trappers were able to trap up to 20,000 rabbits a week in the Cocklebiddy area (Morrison 1948). An abundance of rabbits made commercial hunting still profitable in 1967. Rabbits are almost certain to have very adverse effects on the seedling regeneration of mallee eucalypts (Parsons 1968) and that of many other plants (ITall, Specht and Fardley 1964) in this area, Native animals are discussed by Tate (1879) and McEvey and Middleton (1968), while sheep and cattle grazing has occurred in the area since the 1870's (Dunkley 1967), Hundreds of tons of bitter quandong (Santalum sp.) have been cut from the area for incense making and timber (Brown 1919). Large-scale fires do not occur in the mallee and this area; mallee fres occur only on very hot days and burn out only a few acres (pers. comm., Harvey Gurney, Eucla). DISTRIBUTION OF MALLEE VEGETATION The term mallee vegetation is used here to include all communities domi- nated by mallee species of Eucalyptus, The distribution of mallee vegetation in the South Australian part of the study area based on field traverses is shown in Fig. 4. F - “1 lan" |r $ OUTH AUSTRALIA ESTERN AUSTRALIA AUSTRALIAN T GREA TL Mollee scattered 3 > Miles, on . fo ° \o a0 te SS Mallee predominant Kins 32° az 2° io" 3" 1 - Fig. 4. Approximate distribution of mallee vegetation in the South Aus- tralian part of the Nullarbor Plain, “Mallee predominant” indi- cates 50% or nore of the aréa carries mallee eucalyplts; “mallee scattered” indicates less than 50% of the area carries mallee eucalypts. A vegetation map of the Westem Australian purt of the area will be published shortly by Dr. J. $. Beard, King’s Park and Botanic Gardens, Perth. All that needs to be said here about the Western Australian sector, is that (1) Mallee is pre- dominant along the top of the entire Hampton Range but thins out north of this and disappears at about 20 miles (32 km) north of the Eyre Highway. (2) Mallee is predominant on all that part of the Nullarbor Plain west of Madura and south of the Eyre Highway, (3) Mallee is predominant in the western part of the Roe Plain, but becomes increasingly scattered, and almost confined to a narrow coastal strip, towards the cast. MALLEE VEGETATION OF THE SOUTHERN NULLARBOR 231 All the mallee on the:southern Nullarbor Plain is in areas wetter than 8 inches (20 cm) mean annual rainfall. Mallee eucalypts occur all the way between the large mallee areas in Western Australia and Eyre Peninsula except for a complete break of 16 miles (26 kin) west of the Head of the Bight, the driest part of the suuthern Australian eoasUine, where mean annual rainfall is probably slightly creater than 8-3 in (210 mm), the rainfall at Nullarbor. Mallee is usually predominant in arcas wetter than about 10 m (250 mm) mean annual rainfall. The absence of mallee from large areas in the east of Roc Plain, while it occurs to the north in presumably drier areas along the Hampton Range js diffenlt to explain. Much more rainfall and soil data are obviously necessary. In the wetter south-west of the Roe Plain, mallee is widespread on the shallaw loamy soils on Tertiary limestone and on dunes of all ages. In drier parts of the Plain, especially in the east, it tends to be more common on sandy dune soils because these. are likely to supply more water to plants in this area than the loamy ones (Rowan and Downes 1963). In general, mallee occupies the wettest parts of the Nullarbor and Roe Plains; in drier areas it is replaced by a variety of vegetations, including Acacia sowdenii woodlands and shrub steppe (Willis 1951, 1959). STRUCTURAL TYPES DOMINATED BY MALLEE EUCALYPTS (a) Heath Although Fig. 4 shows “mallee predominant” at the coast, both here and at the coast south of Caiguna, there is a zone of heath (Wood and Williams 1960) for about 500 feet. (160 m) behind the sea cliffs from which eucalypts are absent. Landward from this is a zone of heath from #1 mile (800-1600 m) wide con- taining mallee eucalypts up to 5 feet (1-5 im) high. Melaleuca larcenlata is common and often dominant in this heath, for which floristic lists are given in Appendix 1 (Site 1, 2 and 13). Asymetric growth forms and leaf tip necrosis suggest that wind-borne salt spray is important in inaintaining the low stature of this vegetation (Parsons and Gill 1968) and high evapotranspiration caused by wind exposure is probably also effective. Landward from the heath, taller mallee cucalypts become dominant (sce also Tate 1879), (b) Sesmni-Arid Mallee This sub-form of Wood and Williams (1961) is widespread on the loamy soils of the Nullarbor and the Roe Plain, In fact, except for the coastal heaths, this was the only mallee vegetation found in such soils to about as far west as Cucklebiddy. Height of the cucalypts ranges from 5 feet (1-5 m) where the sub-form grades into heath, to about 30 feet (9 m). Melaleuca quadrifuria is a frequent co-dominant with the cucalypts to at least as Far east as a point 16 miles (26 km) east of the South Australian border (Eats 1 (a)). M, lanceolata is a common large shrub and Cratystylis conocephula the most widespread small shrub, usually occurring with a lurge number of chenopods (Appendix 1, Sites 3 and 4), This type of semi-arid mallee is also found on old dunes (Site 5). Another type found on dunes on the Roc Plain has a denser eucalypt stratum and a sparse understorey dominated by Rhagodia preissit (Sites 7 and 12), A third type seen is found on the scarp of the Hampton Range (Site 6). Lastly, a distinctive type with an understorey dominated by Triodia cf. searlosa is found both on sandy dune soils (Site 9) and in small patches on loamy soils on the Nullarbor Plain south of Cocklebiddy and Caiguna. 232 R. F. PARSONS (ce) Sclerophyll mallee This sub-form of Wood and Williams (1960) was found on dunes on the western Roe Plain as far east as site 8 south of Madura. The dunes carry mallee euculypts and scattered trees of Callitris verrucosa up to 15 feet (4-5 m) high with a dense understorey (Plate 1 (b)) containing sclerophyllous shrubs like Hakea nitida and Beaufortia empetrifolia ( Appendix 1, Sites 8 and 11), This type was found only on dune soils of siliceous sand over limestone (Table 1). On the Nullarbor limestone from 6 miles (10 km) south of Caiguna, to the coastal heath, sclerophyll mallee with a dense understorey dominated by Cusua- tina helmsti occurs (Site 14, Plate 1 (c)). It also appears on such soils from 6-11 miles (10-18 km) south of Cocklebiddy. Thus this type occurs on the wettest areas of Nullarbor limestone cxamined. In drier areas it grades into semi-arid mallee with Cratystylis conocephala as the dominant shrub. DISTRIBUTION OF EUCALYPTUS SPECIES (a) Eucalyptus socialis This is the species whose southern Nullarbor and Roe Plains representatives were known as E. transcontinentalis or E. oleosa var. glauca before the work of Brooker (1968). It has the driest lower rainfall limit of the eucalypts in the area, as it extends farthest to the north and west in that part of the Nullarbor Plain studied (Fig, 5). In all such marginal areas examined, a band of E, socialis was the northern or westernmost mallee found. Thus a more or Jess continuous zone, where E, socialis is the only eucalypt, may euclose the wetter mallee areas, where E. socialis and other eucalypts occur. The only known break in its east-west distribution is one of 16 miles (26 km) just west of the Head of the Bight (Table 2). (b) E. oleosa This taxon was generally known as both E. oleosa and E, oleosa var. angusti- folia hefore the work of Brooker (1968). It oceurs on the Nullarbor and Roe Plains to at least as far east as Koonalda (Fig. 5). It is rare south of Koonalda, and may not occur much further east, giving a maximum possible break in distri- bution of about 52 miles (82 km) before it reappears on sandy soils near the Head of the Bight (Table 2). No other definite east-west breaks are yet known in the area. TABLE 2 Edaphie cange aad doyree of discontinuity for a number of trees species. ‘Discontinuity’ indicates moximum possible size of main pap in east-west distrihmtion in the Nullarbor Plain area. Boil Species } - Disconticuity Loams on Deep Siliceous miles. (kin) limestone ealearcous sancdl* : sand Kucalyptus socialis x x : 16 (25) BR. oleasa. x x x HZ (82) Ee. gracilis xX x x fid (102) E. dumosa complex x < x 163 (245) EE. inergasata x 268 (429) EB. foesunda x | x 372 (595) Li. dinersifolia x i x 312 (499) #. cooperana i | x Not applicable * Includes siliceous sand over limestone. 28 MALLEE VEGETATION OF THE SOUTHERN NULLARBOR ‘spaoga1 uMNTIeqial{ 1OF ‘ABMUALT SIAR SMOYS OUT] asTEOT ‘suOTBOyHUapL pyoy tof spoquids uado spoquids paso] ‘peaids ysam-jsva ut sded UMOUY UL DijOjisyeAip"Z 40, dos sy/201B 3 30) dog I MOYS ‘Hale ApHys ayy UE saiads WYysta fo voHNqIsiqY ‘¢ “ALT DO ejessesoul'y V¥ esoajo'y @) $1/0120$ ‘7 40) dog — v Om epunsao) 9 Vv si|2I008 ‘9 @) 234 fi. F. PARSONS The extension of E. socialis into areas drier than those supporting E. oleasa in the present study seems to occur elsewhere too, Thus in New South Wales E. socialis extends much further north of the 10 in. (25 cm) mean annual rainfall isohyct than E. oleosa (pers. comm, M, I. H. Brooker, Western Australian Herbarium, Perth), and in South Australia at Chowilla Station (mean annual rainfall 8-5 in (22 em)), E. socialis is found (Kuchel 1967) noted as E. trans- continentalis) while E. oleosa does not occur betore wetter areas are reached, (ce) E. gracilis Although this species was not found on the Nullarbor Plain in areas drier than about 9 in. (23 cm) mean annual rainfall, it is recorded from sandy areas north of the Plain around the 7 in. (18 em) isohyet (Ford and Sedgwick 1967), (d) E. dumosa complex This group is in need of taxonomic revision (Burbidge 1947) so no attempt was made to identify the complex to species level in the field, Merbarium speci- mens taken were identified as E, brachycalyx, E. conglobata and E. rugosa (see Appendix 1 for distribution). This complex has not been found on the Nullarbor more than 28 miles (45 km) east of Eucla, nor during a very brief inspection of the sandy country at the Head of the Bight. The nearest eastern record seems to ee an E. dumosa complex specimen (FRI 17848) from 15 miles (24 km) west of undroo. The wetter lower rainfall limit of the E, dumovsa complex than E, socialis, E. oleosa and E. gracilis found in this study has also been noticed elsewhere (Jessup 1948). (c) E. inerassata This name is used to include the varieties costata and angulosa, Tt was uot found anywhere cast of Madura, and the nearest castern record is that of Cleland (1966), 30 miles (48 km) east of White Well. The record of EF. incrassata near Eucla cited by Willis (1951, 1959) and McEvey and Middleton (1968) is now known to be an error; the specimen is E. dumosa complex (pers. comm,., G. Chip- pondale, Forest Research Institute, Canberra). The occurrence of E, incrassata only on sand topsoils (Table 2), in dry areas around its lower rainfall limit has been noted in other arcas (Parsons and Rowan 1968). [ts general distribution has been discussed elsewhere (Parsons 1969). (f) E, foecunda Like E. incrassata it was not found east of Madura; in this case the nearest record to the east appears to be near Koonibba (Cleland 1966 as E. leptophylla) giving a gap of 372 miles (595 km). It has been recorded on finer-textured soils than E. incrassata both in this study (Table 2) and elsewhere (Parsons and Rowan 1968). ‘This suggests a definite difference between the two species in edaphic range, despite their frequent occurrence together in many areas ( Litch- ficld, 1956). (g) £. diversifolia This species is dealt with by Parsons (1989), and will not be discussert Further here. (h) £&, cooperuna This Western Australian species was only found throughout the area af siliccaus sand over aeolian calcarenite north of Twilight Cove (Plate 1 (d)), MALLEE VEGETATION OF THE SOUTHERN NULLARBOR 285 This is the eastern-mast locality from which the species has been recorded {Gardner 1961), (i) E. micranthera This Western Australian species appears to he the only other eucalypt recorded from the area (from near Eyre by Gardner 1960); it was not found during the present study. DISTRIBUTION OF MELALEUCA LANCEOLATA The distribution of M. lanceolata was carefully noted to supplement the viluable introductory accounts of its distribution given by Willis (1948) (as M, pubescens), and Blake (1968). Intensive work has reduced the 170 mile (272 km) distbution gap cast of Eucla recorded by Willis (1948) te 70 miles (112 kn (Fig. 5). Along the Nullarbor coast M. lanceolate is found in the driest areas in which mallee encalypts occur and this is also true at Koonamore Station ( Clapro- dus, Specht and Jackman 1965); elsewhere it seems to be absent from the dviest mallee areas (Jessup (1948) as M. pubescens), DISCUSSTON The eucalypts show two main types of distribution, Li. socialis, F, oleosa, f. gracilis and the E. dumosa complex are frequent and widespread through most of fhe mallee area, while E, incrassata, E. foecunda and E. cooperana. are found only where mean annual rainfall exceeds about 11 inches (28 cm), Eucalypt distribution on the silicequs sands shows some interesting features. The driest area of siliceous sands examined carried EF, oleosa, E. gracilis and the E. dumosa complex (Site 9). In wetter areas, such soils carried E. incrassata, £. foecunda and E. cooperana (Sites 8 and 11). E. incrasata and FR. cooperana were only recorded on siliceous sands, which may be because sands are likely to le Better water suppliers to plants in this climate than the much more widespread OAs « However, the role of soil chemical factors also needs to be considered. Are any other species found only on siliceous sands and not on the more alkaline Joams? The selerophyllous flora of the siliceous sand arca is much richer in species than the surrounding flora on loam soils, und 27 plant species were found only on siliceous sand and not on the wetter loam country south of Caiguna (Appendix 1), Many of these 27 species seem to occur principally on siliceous sand plain areas west of the Nullarbor (Beard, no date), It is possible that many of these species are unable to tolerate soils as alkaline as the Inams on limestone. If so, then much of the flora of the siliceous sand areas of the western Roe Plain is completely isolated from similar areas by edaphic barriers;—the large expanses of loams on limestone of the Nullarbor and Roe Plains. South west of Twilight Cove, the Nullarbor limestone continues for about 65 miles (104 km) before sand dunes are reached near Pt. Culver. Some of these dunes are known to be siliceous (Fig, 2) hut the sands near Pt. Culver are poorly known botanically. The simplest hypothesis ta account for the apparently isolated species occurrences on siliceous sand in the western Roe Plain is to poshilate a continuatus strip of siliceous sand fopsoils linking the Roe Plain with siliccous sand areas further west during Quaternery low sca levels. This could provide continuous species distributions which were subscquently fragmented by rising sea Ievels (Parsons 1969). This hypothesis could account for the occurrence of many of the species confined to siliceous sand in the western Roe Plain. One notable exception is 236 R, F, PARSONS Spyridium spathulatum, known elsewhere in Western Australia only from the Rawlinson Range. Of the two encalypts which were only recorded from siliceous sand, E, incrassata is known from shallow loamy soils on limestone in wetter areas else- where (Litchfield 1956), while E. cooperana appears only to have been recorded from sandy non-caleareous topsoils, both in the Roe Plain and elsewhere. Discontinuities in the east-west spread of all the eucalypts were noted. As all except £. cooperana have been recorded on shallow loams ou limestone {Table 2; Litchfield 1956), there are probably no edaphic barriers to the spread of these other species in the area, The known gaps in distribution (Table 2) coincide with the driest parts of the coastline, A habitat suitable for continuous east-west distribution of these species could thus be provided by an increase in effective rainfall, Alternatively, lower sea levels in the Last Glacial would produce a coastal lowland south of the present coast and jn a wetter latitude (Parsons 1969), which may have provided a suitable habitat. Although attention has been focused here on major gaps in the east-west spread of the specics, there are a number of interesting disjunct occurrences to the north of tho study areca; E. foeeunda at Ooldea and Tarcoola (Burbidge (1947) as E. leptephylla), E. dumosa complex at Maralinga and Melaleuca lancet at Ooldea (Willis 1948). The significance of these must await further study, ACKNOWLEDGEMENTS It is 2 pleasure to thank Mr. P. G. Saenger for invaluable help with the field work, and the State Herbatium of South Australia, Mr. L. A. 5, Johnson, Mr, R. F. Blaxell, Mr. J. H. Willis, Mr. B. D, Royce, Mr. G, M, Chippendale and Mr. M. IL. II. Brooker for taxonomic assistance. REFERENCES Ausimitaa; Bunga or Mzreorcrocy, 1956, ‘Climatic Averages Australia” (Burean of Meteorology:. Melbourne ). Hranp, J. S. (ed.), no date, “Descriptive Catalogne of West Australian Plants (Sve, for gvowing Aust. Plants: Sydney). HiAKn, $. T. (1968). A revision of Melaleuca leucadendron and its allies. Contrib. Qld. Herb, No, 1, Bucoxen. M. I. H., 1968. Phyllotusis in Eucalyptus socialis KF, Muell. and £, oleosa F- Mucell. Aust, J. Bot, 16: pp. 455-468. Bnown, T., 1919. Nullarbor Plain. Proc. 5. Aust. Brelt. BR. Geowr, Soc, Aust, 19: pp. 141-152. Burswer, N. T., 1947. Key to the Sonth Australian species of Eucalyptus. Trans, R. Soc. Aust. 71: pp, 137-163, Casnopus, B. B.. Srpecur, K, L., and Jackstan, M- L.. 1965. The veretation of Koonamury Station, South Australia, Trans. R, Soe, S,A,, 89: pp, 41-57. CLELAND, J. B., 1966. West coast plants. S. Anst. Nat. 40: pp. 53-65. Duwecey, J. R, (1967). The geographical and historical background. In Duukley, J. R., and Wiyley, T. M. L. (eds.), “Caves of the Nullarbor” (Speleological Research Canncil: University of Sydney). Eiki, 4 f 1965). “Supplement to J. M. Black’s Flora of South Anstralia” (Govt. Printer, Adelaide). Forp, J., and Sepewrcx, BE. H., 1967, Bird distributivn in the Nullarbor Plain and Great Victoria Desert yegion, Western Australia. Emu, 76: pp, 99-124. Gannwen, Co A, (1980). Trees of Westem Australia no, 63-70. W. Aust. Dept. Agric. Thull, Nu. 2755, Canonen, C, A. (1961). Trees of Wester Australia no. 83-86, W, Aust, Dept. Agric, Bull. No, 2846, MALLEE VEGETATION OF THE SOUTHERN NULLARBOR 237 Hatt, E, A. A.. Srecur, R. L., and Earnwy, C. E., 1964. Regeneration of the vegetation on Koonumore vegetation reserve, 1996-1962. Aust. J. Bot... 12: pp. 205-264, Jexnines, J, N,, 1963. Some geomorphological problems of the Nullarbor Plain. Trans. R. Soe. S. Aust., 87: pp. 41-62. Jesnincs, J, N. (1967), The surface and underground geomorphology. In. Dunkley, J. R., and Wigley, T. M. L. (eds.) “Cayes of the Nullarbor”, ( Speleological Research Connuil: University of Sydney.) Jessur, R. W., 1948, A vegetation and pasture sarvey of counties Eyre, Burra and Kimberley, South Australia. Trans. R. Soe. S. Aust., 72; pp. 33-68, Keone, R, (1967). Vegetation of the Chowilla arca. Univ. Adclaide Dept. Adult Education Publ. No. 6: pp. 32-40. Luertn, G. W. (1960). Climates. In. "The Australian Environment”, 3rd ed. (G.S.1.B.0. Aust.; Melbourne. ) Litcirienp, W, H,, 1956. Spevies distribution over part of the Coonalpyn Downs, South Australia. J. Bot., 4: pp, 68-116. McEvey, A. R,, and Mimprerox, W. G., 1968. Birds and vegetation between Perth and Adelaide. Emu, 68: pp. 161-313, Mosrison, P. C., 1945. We went west: Eucla to Cocklebiddy. Wild Life, 10; pp, 119-124, Nonrucote, K. Hi, Berrenay, E., Caurcuwarp, IT, M,. and McAutuun, W. M. (1987), “Atlas of Australia Soils. Sheet 5”. (C,S.1R.O, Aust.: Melbourne. ) Norracote, K, H, Issein, K. F., Wren. A. A., Muntia, G. G.. Cayuncuwarp, H. M.. and Bettenay, E. (1968). “Atlas of Australian Soils. Sheet 10” (C.S,1R.O. Aust. MeJbourne. ) Parsons, R, I, 1969. Distribution and palaeogeography of two mallee species of Evcalyptux in southern Australin, Aust. J. Bot. 17: pp. 323-330. Parsons, R, F.,. and Giron, A. M., 1967. The effects of salt spray on coustal vegetation at Wilson's Promontory, Victoria, Australia. Prac, R. Soc. Vic, 81: pp, 1-10, Rowan, J. N., and Downes, R. G, (1963). A study of the land in norti-western. Victoria, Soil Conservation Authority Vic. Tech. Comm. 2. Tats, R,, 1879. The natural history of the canntry around the Head of the Creat Anstralian Bight, ‘Crans. Phil. Soc, Adeluide for 1879: pp. 94-128, Witus, J. H., £948. On the nature and distribution of “moonah” { Melaleuca pubescens Schauer). Vict. Nat, 65: pp. 76-84, Witus, J. 1, 1951, Botany of the Russell Grimwade expedition, Mem, Nat. Mus. Vic., 17: pp. 33-64. Witus, J. H., 1959, Notes on the vegetation of Eucla district, W.A, Muelleria, 1: pp. 92-96, Wiuiis, J. H., 1965, F.N.C.V. excursion to Western Australia, August 31—September 22, 1963, Viet. Nat. 81: pp. 330-337. ; Woon, J. C., and Wraams, BR, J. (1960), Vegetation. In “The Anstyalian Environment” 3rd] ed. (G.S.1,R,0. Aust; Melbourne. ) APPENDIX 1 Occurrence of plant. species in 14 mallee communitins. For lneation of sites see Fig, 2. For structural type of each community see text. Column 144 lists herbarium specimens cullected and ideutified by Mr. P, G. Wilson between ‘aigiiin and the coast south of it. All these are held at the Western Auatrelian Herbarium, h herbarium specimen f = field identification; no specimen taken n = herbarium specimen from within 26 kam of site indicatedt Ww = recorded by Willis (L941, 1966) x = not recorded from South Australia (by Eichler 1965) + = recorded only on siliceous sand topsoils in this study Taxonomic nomenclature follows Beard (ho date) for plants restrictad to Westurn Ansiralia. oul Kichler (1965) for all others, except where mentioned in the text. il Nl ed oR a 13/18 sal Wy { H A ASPLENIACEAR | Plenrosorus rudifolius (KR. Br.) Fée | w CUPRESSACEAB Callitris verrucosa | P ‘ ‘ Bib £ | (A, Cunn, ex Endl.) F vy M.* | a 238 POACEAE Agrostis sp. Amphipngon of, turbinatus R.Br.*~ Danthonia. caespitosa Gaudich, Stipa acrociliata Reader S drummondii Steud. S. eremophila Reader S&S. hemipogon Benth. S&S. seabra Lindl. S. verticellata. Neos ex Spreng. Triodia scariosa cl. Burbidge CYPERACEAE Gahnia lanigera (R.Br.) Benth. Lepidosperma drummondz Benth.* Schoenus aemeria Boeckel.*+ S. lanatus Labill.** S. aviteng (R.Br.) Poir.+ Schoenus pleiostemaneus F vy M.** RESTIONACEAE Lowecarya flexuosa (R.Br.) Benth."* LILIACEAE Bulbinopsis semibarbata (R.By.) Borzi Dianella revoluta R.Br. Lomandra glauea (R.Br.) Ewart Tricoryne elatior Ry, Br.+ CASUARINACEAE Casuarina helmsit Ewart & Gordon C. huegeliana Miq.* PROTEACEAE Adenanthos sericea Labill,var.brevéfolia Benth.~ Grevillea cf. pinaster Meissn.*> Ct. sparsifiora F v M.* Hakea pitida R.Br.** SANTALACEAE Exocarpos aphyllus R.Br, EL. sperteus R.Br. Santalum acuminatum (R.Br.) A.DC, LORANTHACEAE Amyema miguelit (Lehm. ex Mig.) Tiegh. CHENOPODIACEAE Arthracnemum halocnemoides Nees Atriplex acutibraeta Anderson A. hastata L. var. salina Wallr. A. hymenotheca Moq.* Bassia patenticwapis Anderson B. uniflora (R.Br.) Fv M- Enchylaena tomentosa R.Br. Kechia ertoclada (Benth.) Gauba KB. excadata var, trichaptera Black K. planifolia F v M. RK. sedifolia F v M. K. villosa Lindl. Rhagodia crassifolia R.Br. R. preissit Maq. Threlkeldia diffusa R.Br. AMARANTHACEAE Ptilotus obovatus (Gaudich.) Fv M. R. F. PARSONS 2'3'4'5' 6) 7 h h £ ih h lh h h | hi h h h h h h hi} w 8 | 9 ) 10) 11) 12 h te 14 14 h lh | | li | h TN h h i h | h h MALLEE VEGETATION OF THE SOUTHERN NULLARBOR AIZOACEAE Carpobratus sp. Disphyma australe { Ait.) N. E. Brown LAURACEAE Cassytha melantha R.Br. BRASSICACKAE Stenopetalum robustum Endl.® PITTOSPORACEAE Billardiera sp.+ Pitlosporum phytliraeaides DO. MIMOSACEAE Acacia cochlearis Wendl.*+ A. erinacea. Benth. A. ef. nitidula Benth.*+ CAESALPINIACEAE Cassia nemophila Cunn. ex Vogl FABACEAE Bossiaea leptacantha BE. Pritzcl*+ Dasiesia preissii Meissn.*+ Pultenaea obcordata (R.Br. ex Ait.) Benth.*+ Templetonia retusa (Vent.) ZYGOPHYLLACEAE Nitraria schoberi L. Zygophyllum billardiert DC. Z, glacucum F y M. RU'TACKAE Correa reflera var. coriacea P. G. Wilson Geijera linearifolia (DC.) Black Microcybe multiflora. Turez, M. pauciflora Turez. POLYGALACEAE Comesperma polygaloides F v M. 1, volubile Labill. EUPHORBIACEAE Beyeria leschenaultéi (DC) Baill, var. ledifolia (Klotzsch) Gruning | SAPINDACEAE Dodonaea stenozyya F v M. Heteradendrum oleaefolium Dest. RHAMNACEAE Pomaderris forrestiana Fv M. Spyridium parvifolium (Hook.) Benth, ex F vy M. S. spadiceum var, calvescens (Reissek) Benth.* 8. spathulutum (F v M.) F vy M. ex Benth.+ 8. tridentatum (Steud.) Benth.+ Trymalium myrtillus 8, Moore* DILLENIACEAE Hibbertia nutans Benth.* H. uncinata (Benth.) F y M.* 1) 2 h | 3 4/5 | f h h 6 hh 7 8 h Wy 10; 11' 12 | Ww w h h | nh nh w w w h n h 239 13'14;14 ‘A | jhe fj i | h | ja. | | ih lh j | lh oh h i | | ‘hh hy; | jh i } | | h | | ee lh hi lh 246 FRANKENIACEAE Frankenict sessilis Summerh. THYMELAEACEAR Pimelea serpyllifalia R.Br. MYRTACEAE Beaufortia empetrifolia (Reichb.) Schau. *! Calytrix telragona Labill, Rucalyptus brackycalyx Blakely E. conglobata (R.Br. ex Benth.) Maiden E. cooperana F v M.*+ EF, diversifolia Boupl. E, foveunds Schau, EE. gracilis F v M. B. incrassata Labill.+ E. oleosa F v M, ex Mig. BE. rugosd R.Br, ox Blakely EL, socialis F v M. ex Miq- Melaleuca conferta Benth. M. lanceolata Otto M. quadrifares Fv M. EPACRIDACEAK ef. Acrotriche cordata (Labill.) R.Br.* A. patula R.Br. Conastephium sp.— Leucopogon aff, aquarrosus Benth.** Lysinemea ciliatum BR, Br*> Styphelia hainesit F v M.* LOGANIACEAE Logania stenophylla F v M. BORAGINACEAE Halgania ny. lavandulacea Endl, LABIATAE Prostanthera microphylla A.Cunn. ex Benth. Westringia dampieri R.Br, W. rigida R.Br. MYOPORACEAE Hyremophila alternifolia R-Br. var. latifolia F v M. ex Benth. E. decipiens Ostenf.* E. dempsteri F v M.* EB. welilitt Fy M, Myoporum ap. GOODENIACEAER Goodenia sp. G. affinis De Vriese Lechenaultia ef. tubiflora R.Br.*+ ASTERACEAL Cratystylta conocephala. (F v M.) 8. Moore Heliplerum floribundum DC. Olearia exiquifolia Fv M. O. muelleri (Sond.) Benth, O. pimeleoides (DC.) Benth. Podolepis rugata Labill. Senecio aff, lautus Forst. f, ax Willd. R. F. PARSONS 1|2 h|h h hi h ih ~”AR h h 3 a 4 h h, 5 | 6 h \ 'h | h: h. h h | h jh h | he h | | | h h h h 9/10 Ww 24 h h h h | 13 hi! n h h 14 h | 14 A h h ih 241 EXPLANATION OF PLATE PLATE 1 (a) Tall semi-arid mallee on the Roe Plain 14 miles (22 km) south of Moodini. Eucalyptus gracilis on right; Melaleuca quadrifaria on left and in background. Figure is six feet tall. (b) Sclerophyll mallee about 12 feet (4 m) high at Site 11. Eucalyptus diversifolia on left; Callitris verrucosa on right. (c) Sclerophyll mallee about 8 feet (2-7 m) high at Site 14. Eucalyptus socialis and Casuarina helmsii are clearly visible. (d) A stand of Eucalyptus cooperana 1 mile (1-6 km) south of site 11, showing the charac- teristic, starkly wnite stems. PLATE | R. F, Parsons (b) (a) CANOPY DYNAMICS OF TREES AND SHRUBS WITH PARTICULAR REFERENCE TO ARID-ZONE TOPFEED SPECIES BY J. R. MACONOCHIE* AND R. T. LANGE Summary A study is reported in which foliage gain and loss was followed in canopies of tree and shrub populations. Data are presented tracing concurrent1 quantities and rates of leaf gains and losses in stands of five arid-zone topfeed species in stands at Yudnapinna, South Australia, during the period May 1965 to January 1967. These data are examined also with reference to time of year and rainfalls, which occurred during the period. The performances of the five species are grouped into three categories characterized with respect to various features such as number of phases, synchronization of foliation and defoliation, and seasonal periodicity. The significance of both method and results in revealing canopy dynamics in arid regions is discussed. CANOPY DYNAMICS OF TREES AND SHRUBS WITH PARTICULAR REFERENCE TO ARID-ZONE TOPFEED SPECIES By J, R. Maconocniz® anp RB, T. Lancet SUMMARY A study is reported in which foliage gain and loss was followed im canopies of tree and shrub populations, Data are presented tracing concurrently quantities and rates of leat gains and losses in stands of five arid-zone topfeed species in stands at Yudnapinna, South Australia, during the period May 1965 to January 1967. These data are exarnined also with reference to time of year and rainfalls which securred during the period. The performances of the five species are grouped into three categories characterized with respect to various features such as nymber of phases, synchro- nization of foliation and defoliation, and seasong] periodicity, ‘The significanue of both method and results in revealing canopy dynamics in arid regions is discussed, INTRODUCTION Topfeed or browse species are those trees and shrubs in rangeland vege- tation which produce stock fodder. Some of this foliage is directly accessible to stock, some is shed to the ground: Mulga (Acacia aneura F.v.M.). bullock-bush (Heteradendrum oleaefolium Desf.) and plum-bush (Sentalum lanceolatum R.Br.) are typical Australian examples. The pastoral importance of topfeeds is recognized and has been extensively discussed; for example, in Joint Publication 10 of the Imperial Agricultural Bureaux it was pointed out that “probably more animals feed on shrubs and trees, or on associations in which shrubs and trees play an important part, than on true grass or grass-legume pustures, short and tall-grass ranges, and steppes”. Topfeeds certainly have importance in the Australian arid-zone. With few exceptions, published data about canopy growth and hence fodder production by topfeed stands in the Australian arid-zone are lacking. Principles for determining productivity of tree stands are well established (Ovington, 1962). Methods refer mostly to forest and agricultural situations where sites, climates and stands are closely specified, cyclic and predictable, and emphasize mean production of timber by weight or volume, or total yield by weight or calorific equivalent. In the Australian arid zone, stands are not closely specifiable because their biology is not well understood, and climate is neither cyclic nor predictable in many important respects, Further, emphasis regarding topfeeds is on foliage alone, and preconceptions, like prior literature on these topfeeds, are absent. It is necessary to adopt an approach consistent with this context. Such an approach, implemented in this study, has yielded relevant data about production rates of arid-zone topfced species, and this paper reports and discusses the approach itself and results obtained by its use. METHODS For cach species the study unit was the accessible outer foliage of the natural stund, regarded as a population of shoots. This population was sampled by * Animal Industry Branch, Northern Territory Administration, Alice Springs, NT, # Departuent of Botany, University of Adelaide, South Australia. ‘Trans. R. Soe. S. Aust. (1970), Vol. 94, 244 J, R, MACONOCHIE ano BR. T, LANGE restricted randomization, that is, the total stand was first sectored and then random samples were drawn pro rata from each sector. A tag was affixed on each sampled shoot axis hetween the sixth and seventh leaf or leaf-bearing position proximal to the apex, Between 100-150 samples were tagged per stand. Total leaf number distal to tags was regarded as initial capital or quantity, susceptible to gain and loss. Records were kept of leaves and leaf-bearing positions on indi- vidual shoots; changes in leaf numbers were thus obseryed and recorded at intervals during a protracted period, The use of tags for this purpose is well known (Nelson 1930, Njoku 1963). ~ af A wh pps 3 ae ies Big \o 50) 6 a8 a aa * aie a) B38 = TLL ae sda 5 @©wosa F MAM YY 5 #£ SFE QOnOy sal Lave iaee Tae? Fig, 1. Shows mean maximum daily tem- perature (°C} and accumulated rainfalls (mm) for successive periods, Experimental sites were located on Yudnapinna Station (an arid-zone pastoral lease in Sonth Australia) at lat. 32.2°S, long. 137.5°E, in vegetation deseribed by Jackson (1958), who also described associated climate, physiography and soils. Chmatic data for the period were obtained from the Yudnapinna records of the Commonwealth Bureau of Meteorology. The species studied were Acacia sowdenti Maiden, Myoporum platycarpum R. Br., Heterodendrum oleae- folium Desf., Cassia nemophila var, coriacea (Benth.) Symon and Cassia nemo- phila. var. platypoda (R. Br.) Benth. Voucher specimens are deposited in the State Herbarium of South Australia. RESULTS Summarized data are presented in figures 2 and 3, Figure 2 shows the course of cumulative leaf gain, cumulative loss, and cumulative gain/loss balance for each of the five species; Figure 3 shows rates of gain and loss for cach of the five species. Figure 1 shows graphs of mean maximum daily temperature, and accu- mulated rainfalls for successive periods, in the study area. The five species fall into three categories on differences and similarities of performance, Category I A. The Heterodendrum oleaefolium stand (Figs, 2d: 3a). Observations began in April 1965, No changes occurred until August, after meun teniperatures rose from their winter low. Foliation and defoliation then sccurred at more or less equivalent low rates util November, after which rates increased until February 1966. Net gain within samples was then about 25%. With the passing of peak summer temperatures, foliation rates fell to near zero. by September, as did defoliation rates. From February to October 1966 net foliage declined by about 20%. Again when temperatures began to rise in CANGPY DYNAMICS OF TREES AND SHRUBS 24% summer, rates of foliation and defoliation increased until December and began to decline by January 1967, Net gain to initial capital was about 75% when observations ended. The following points are established: (a) This stand exhibited canopy dynamics which appear to be cyclie en a seasonal basis, (In this locality rainfall is net seasonal hence “season” implies only temperature and photoperiod cycles. ) {b) The characteristics of these canopy dynamics were (i) rates which increased rapidly in spring from near zero, sustained high yalues until thermal midsummer, then declined gradually to very low rates by thermal midwinter; (ii) synchronous and similar rate changes in foliation and defoliation; (iii) the differences in the magnitude of these rates caused net increases in the period November to February, with little change or slight decline over intervening periods. (c) Foliation and defoliation rates changed irrespective of rainfalls, and showed no direct response to rainfalls, B, The Acacia sowdenii stand (Figs. 2b; 3b). The performance in this stand was generally similar to that in the Hetero- dendrum oleaefolium stand regarding cyclic rate changes, no ohyious reaction to rainfalls, and net losses during winter. There are however differences in particulars, namely (¢) curve inflexions occurred later in summer, (ii) folia- tion and defoliation rate changes were not well synchronized, and (iii) a higher net gain was attained over the period. Catezory IT The Myoporum platycarpum stand (Figs. 2c; 3c). This performance, like those in category 1, showed no direct reaction to rain- falls, but differed in that higher rates of foliation were sustained longer and rate changes were gradual rather than sharp. Net gains were sustained during the entire period, and ultimate net gains were considerably higher than in Category I. Since all curve inflexions were relatively suppressed, so was expression of foliation/defoliation synchronization, and apparent seasonal cycle, Crtegory U1 A. The Cassia nemophila var. platypoda stand (Vigs, 2a; 3d). This performance differed markedly from those of other categories in that three phases of rate-change ovcurred during the period where other per- formances exhibited only two. Rainfalls were the only non-seasonal enviren- montal variables measured; there was no obvious relationship between the timing of these and the midle phase of rate-change, Substantial nett loss accurred between the last two phases of rate-change. There was no close relationship between rates of foliation and defoliation. Overall net gain was comparable wtih Category II, B, The Cassia nemophila var. coriavea stand (Figs, 2e; 3e). This performance was essentially similar to that of Cassia nemophila var, platypoda, viz.: three phases of rate change instead of two. Net loss was sustained between the first two of these; overall net gain was lower. 246 J. R. MACONOCHIF anp R. T. LANGE eo Laecta namophile var. platypoda ti 2 E aoo 3 300 g {a0 F 1b+— : see : oo ea Se ee Ce Misa SOHO FAR wad aA SOND SG Lies ise 1386 (a) Myoporurt niatyearpun soe / 300 200 ca] 190 Bay Bc} a 0 3 z 3 00} 3 ' a 204) eb bby bp yp wis ASONDI FRAMS FAR OW DI 1366 T968 ioev (eo) Lifecta wemoplida tar. contazea Gaver wriulattpe hereentage O58 eo of ‘ ? a percentage aun cwmiative pepoeneage love pain a 6’ 2 = Ned 5 3S s TTT TTT Tt ~ wy sek SOWOTFMAHT SAS OW D + 1985 tase (e) Zt sey feacia Bowel oumlabive percentage lJ Hila SOM DIFMAMs Ja SON DG z tee igee (hs) Heterodendmm oleae foliun aumiatite percentage Lose an 2 Mig & 30 WOES F Maw Ss dA HO KD YD Tah inet Tig. 2.On the ordinates, zero represents initial leaf number, other values are percentage cumulative gains and losses to initial number. The abscissa is sealed for dates. and intervals of time. The upper broken line records the course of cumulative new leaf gain relative to initial number. similarly the lower line records cumulative leaf loss and the solid linc records cumu- lative gain/loss balance. DISCUSSION The first noteworthy feature is that of apparent seasonal regularity in the way some species gain and shed leaf. There are two aspects to this, first, rainfall (8 in, annual average in the area) is erratic and, apart from slight elevation about February, monthly averages over 30 years are about equal; second, apparent cycles of growth coincide with the build up and climax of high summer tem- peratures and related water-stress. This sitnation parallels that in Dark Island Heath (Specht 1957), where main growth is in summer at times of soil waler depletion. As opposed to such heath, these Yudnapinna stands are ‘not even vuaranteed a predictable wet winter. Such growth phenomena remain unexplained. The sccond important feature is variation in performance between stands. If eventual consideration be given to the informed use of arid-zone topfeeds, atten- tion must be directed then to the implications of this variation. Thus the timing Lae? CANOPY DYNAMICS OF TREES AND SHRUBS 247 of Category I production phases appeared to be predictable from a knowledge of date alone, and independent of the timing of particular rainfalls. This predicta- bility attached, in Helerodendrum “léaefolium for example, to both fresh leaf production and litter drop. Category IIL stands, in contrast, represented a differ- ent kind of topfeed, since they displayed three phases of activity versus two for other species in their immediate vicinily, The Category II species represented yet another type, where leaf gain proceeded in a relatively even fashion while activity in other stands either accelerated or declined. There is certainly no suggestion that Yudnapinna topfeed stands all behave alike. Most Yudnapinna stands exhibited periods of activity not related to particular rainfalls despite the arid habitat, which offsets any idea that “likely effectivencsss” of precipitations (Beard 1968) is necessarily a first issue in the performance of arid-zone plants. E G 5 & 3 -nodendiren Soltwm ri ; 5 v aepenaderainp yckgeday viet & 60 4aqeia Aouile rh rar) i 3s x . & 2 a 3 338 3 £ Bt sat 4 oes ete AgYe = Foals : ipre isee aH (a) (b) 2 slatuccrDpu she, 4 Hyogo mien praegocrpyt 5 fadsie nemopitia var. platypada 8 a4 43 a} 3 28 2 § 23 g 3% 3 % a y om a wu » zs $8 3 ES = 8 g 4 a 3 “p ey tees Leaé Lge? hoe dos lade tee? 4 ' (ce) (d) Seasia nemopiidd var, eoniacar Vig. 3. Graphs show rates of gain and loss of leaves on the five species, for successive time intervals (per period, | final-initial quantity | / initial quuntity, %). (e) Figures 2 and 3 show that topfeed canopy dynamics are revealed simply and clearly by lagging; a further step might be to relale sampled population to total stand canopy. This would be difficult; it is much more complex to document the course of events on every branch in the canopy, with respect to every leaf and bud it bears between its apex and most proximal leaf. The oldest leaves furthest from the shoot tip are more likely to fall than the tip leaves; taken into account, this would reduce percentage net gains to different, lower figures. Similarly, top canopy shoots and inner canopy shoots perform differently to each other and to 248 J. R. MACONOCHIE anv R. T, LANGE accessible shoots, Eventually, consideration of limb and whole plant input and death might be nevessary, In practical terms, learning the added information might not justify the effort. Recourse to other techniques such as litter-trapping (Bray and Gorham 1964) might be explored first, since the question of what information is desirable must be balanced against the cost of obtaining it. No available method, however, appears superior to counting leaves on tagged shoots possibly combined with measurements of shoot length for following canopy dynamics, where the purpose is the interpretation of arid zone stands as range- land fodder components. Ultimately, best advances may be made by considering stand production as of an assemblage of specified individuals studied separately. At present information is lacking whereby stand composition may usefully be specified; the typical Australian topfeed stand is an unknown entity regarding, internal age and stage relationships, although data are accumulating. Synchronization of foliation and defoliation in Heterodendrum oleaefolium prompts ideas that this synchronization holds for individual trees, that internal nutrient cycling could be involved, and that interesting physiological mechanisms will be found responsible. Further attention to this must awuit investigations of individuals, not of the stand as a whole. ACKNOWLEDGEMENTS The authors are grateful to the Rural Credits Development Fund of the Reserve Bank of Australia for financial support, to Mr. Dean of Yudnapinna Station for cooperation and help, and to numerous colleagues for assistance. REFERENCES Brann, J. &., 1968. Drought effects in the Gibson Desert. J. Roy. Sac, W.A, 51, pp. 39-50. Bray, J. R., and Gonsam, E., 1964. Litter production in forests of the world. Adv. in Ecol. Res, 2, pp, 1Q1-157. Jaceson, EF. A., 1954, Soils and hydrology of Yudnapinna Station, S.A, C.S.K.O. Soil und Land Use Series No, 24. Jomvr Avruons, 1947. The use and misuse of sliuwbs and trees as fodder. hop. Agric, Bureaux Joint Publication No, 10, NBECR, mM W., 1980, Methods of studyimg shrub plant in relation to grazing. Ecol 2, pp. 764-769. Nyoxv, E., 1968. Seasonal periodicity in the growth and development of some forest trees in Nigeria. J. Ecol. 51, pp. 617-624. Ovincton, J, D,, 1962. Quantitative ecology and the woodland ecosystem concept. Adv. in Ecol. Res. 1, pp. 103-192, Srecur, K. L., 1957. Dark Island Heath (Ninety-mile plain, South Australia), V. The water relationships in heath vegetation and pastures on the Makin Sand, Aust. J. Bot, 5, pp. 151-172. OBITUARY: FRANCIS JOHN MITCHELL, 1929-1970 Summary pre pee] OBITUARY Francis Joun Mrrermery, 1929-1970 ‘the senior Vice-President of the Society, John Mitchell, died at Belair on February 23rd, 1970, at the early age of 40 years, John was barn at Adelaide on August 8th. 1929, an was educated at the Adelaide Technical High School As a schoolboy he became deeply interested in. reptiles and proficient at their identification, He spent his entice working life at the South Australian Museyrn, joining the staff as a junior vadet in 1946; he was appointer! Assistint Curator of Reptiles in 1955, Curator in 1956 and Senior Curator of Vertebrates in 1965. Mitchell's early research activities were in the field of reptile taxonomy, devoting particular attention ta genera ‘of the lizard families Agamidae and Scincidae. His first papers reveled n maturity of approuch fur in advance of his years; and he rapidly established himself os a highly competent taxonomist, Tn 1964 he commenced a study of the White Dragon Lizard Amphibolurus maculosus (Mitchell) inhabiting the salt crust of Luke Eyre, a step initiating a transfer of his interests to the field of animal behavionr, He visited Lake Myre an mimerous occasions, compiling considerable data on the lizard and its habitat. He designed new types of observation chambers at the Museum and there maintained observations on captive specimens for severa) years. ; John Mitchell had diverse interests and actively promoted most of them. Ile was President af the Skin Divers’ and Fishermen’s Association in 1954, was the South Australian Opon Champion from 1954 to 1957 and won awards at the Australian Championships in 1957. He founded the Underwater Research Croup and ‘was its President froma 1958 to 1964, He acted as a judge for the South Australian Photographie Federation, He was a Foundation Member ol the Australian Society of Herpetologists and for several years represented South Australia on its committee, John served on the Council of the Royal Society of South Australia for twelve years. as: Treasurer (1959-67), Vive-President (1967-68, 1969-70) and President (1968-69), For several years he suffered ill-health but he continued to place his voluntary duties to the scientific community before his personal research interests. The extent of this service restricted his research pirtput hut earned him the sincere respect of those who liad the privilege to be asspeciated with him. SELECTED BIBLIOGRAPHY 1y4s fe Revista of the Lavertitian genus Tympanecryntis. Rec, 5, Aust. Mus. 9 (1): pp. 57-96, 1949 = Fauna mid Flora of the Creenly Islands, Part I. Introductory Narrative and Vertebrate Fava, Ibid 9 (2): pp, 167-179 (with A, C. Belirndt). 50 Scincid Genera E¢ernia dod Viliqua (Lacertilia), Ihid 8 (3); pp. 275-208. 1951 = 'The South Australion Reptile Fauna, Part 1, Ophidia. Thidl § (4): pp. 545-557. 1953 A brief revision of the Four-fingered members of the germs Leiolopisma (Lacertilia). Ibid 9 (1): pp. 75-90. 1955 = Preliminary Account of the Reptilia and Amphibia collected by the National Geo- graphical Society—Commonwealth Govyernment—Smithsonian Institution Expedition to Arvhem Land (April to November, 1948). Ibid 9 (4): pp. 373-408. 1956) = The problem of Polyphylogony in Ausiralian Reptile Classification. 16 pages, roneoud notes, Contribution to International Congress on Southern Hemisphere Vertshrate Taxonomy, Saqa Paulo, Brazil. 1958 Adaptive Convergence in Australian Reptiles, Aust. Mus. Mag. 19 (10): pp. 814-217. 1958 Conmunal Egg Laying in the Lizard Leioloptisma guichenuti (Dumnéril.and Bibran). Trans. BR. Soc, S, Aust, 82: pp, 121-123, 1961 Results of the National Geographical Socicty—Conmmonwealth Govornment—smrith- sont institution Expedition to Amhem Lind: Heptiles and Amphibians 4: pp. 1945) The Affinities of Tympanooryptis muculosa Mitchell ( Lacertiliua—Ayamidae). Ree. 5. Aust, Mus, 15 (1); pp, 179-191, 1965 Australian Geckos assigned to the genus Cehyra Griw ( Reyilia—Gekkonidae}, Senck. Biol. Frankfurt 46 (4); pp. 287-819, M. J. TYLER BALANCE SHEETS: GENERAL ACCOUNT, ENDOWMENT AND SCIENTIFIC RESEARCH FUND Summary a nL U Utd Og" L988 OL6T ‘unl WINE aun[PY FursojD SS'LITS e6'FE sampung sT'oce sulpulg 00'089 duyung Os ZOE saat AA, squawfpg jonpaqd $ $ SLNAUWAVd so°sse's$ 60°E8e'T 66° TOL'T $ LEO " - ‘ - ; pareaodar aneysog OF TO ie " = 7 it ysauoyuy YU CE LST ue t ; saowovsursy, JO ales ager ‘Af JS[ aounjog suruadCQ SLdId9au $ 250 TS OL6T “ANOL 0s GHANA UVAA AHL YO SLNAWAVd ANY SLdIdOdY JO SLNAWALVLS INQOOOY AWVHAI'T a ee SE UEEEE EEUU EEE ESSE 6L'1La6‘IS ~ OLGT ‘aunf Og soun{Pg BuIsO]D SLFR8'OS 6E°396F oO0°0S a “ * Qrsoda) qouurg AjyaI90g 00'6F “4 = " i yaInjoay BUIZISLA Le°S9T 7 ‘ : ~ 7 a t salrpung ¥F'COL aouBinsuy IS LP ‘ ad 7 * * sa AIaWOHES OG'SP " Ht “ " ~ “ safreqd aorAaiag 96' FLAS TS'6L auloauy AIpung 00°S6T "i - “ = i “seg «peg OF T89 ~ sqoriday SoSLT odesog 62'F6 " ysaqaquy puog puw yueg 06" SLT, ; nC ” ‘ -- sso Sururayry 00002‘ query JUAWIUISANL) crosses . 7 4 > “ sysory surysryqnd OF 6TE'T * a - suogdposqng squawfpg janpacy So'GOO'T ‘ i > “ ' 6961 - egyng BT aounjog suuadoQ $ $ $ SLINANAVA §.Ld OSH a EEatEEE ESSE OLGT ‘Unf NOs GAGNA UVAA AHL WOU SLNAWAVd ANY SLdIGORY JO LNAWALVLS LNOOODY IVHAHNAS) CALVYOdUOONI VITVYLLSNY H.LAOS AO ALAIDOS ‘TYAOY ALLL 251 ‘syUBJULODDY pazayEy “OLGI ‘taquraides YIOT “OD ® ADHVAS 'SNAARLS ‘ANIL ‘elerisiy qynog “eprejapy ‘OLGL Ounf INE Ww SjuouNsoAuT Jo aMpaqag oy) payLoa osu dary aA ‘parjimqns Qawog oy Jo SfOOg PYF Aq WAGYS SE PUL sh 0} UdAIA sMOYEUYydaa Oy pur MONRUTOJUL Am 30 Say ayy 0} Murpsog9.u OZ GT ‘autf IYg pepaa avo.t aq} 107 AJaTODg ay] Jo suoNOYsUTLy ysea 94} proood OF dn aavesp Apradoid are puny jeumopuy pue Aug] ‘[e1803 ay} Jos sjusutdeg pur sydroaoy JO spreuAyyS payowye oy ‘word ano uy "parnbes aauy am suonEuEfdxe pur uoNeuuOyUt ogy [Te paureyqo adey pue QZEL ‘anf yg papue mak ayy 10} (CLVHOdHOONI) YIIVULSAV HLNOS JO ALSIOOS IVAOW oy JO MUnOMDy pue syoog ayy pauiexa aaBy am 9eyy poder ai Woday ssoLdaay a OO cE0'ST$ OLET ‘eun{ WINE yoIg ApIUbY Jo onBA JxUyL a70N" TP IS0'ses SE'8es “ ~ 7 Y ct “ yung Ft YstD 00'008 — wy a 7 “ ~ yPoYS paqrosuy 9L'BeVEL OO'SEB it Hi 7 * OO8—PAPYSNY jo stayEuraqny, 00°008, ry ~ ~ 00F—sj1g—saarpjoH poomyus AVOSTT “ ‘ GlLg—soururg YWomens'T 00°e90'T ae “ OOS—Senysapuy peopmayy [euaduiy OO'OE ET f i" : a ‘ SLe—sqoo.L OL'F LS‘ we ii " gsgo—seury, AppeA, pyRsayy FSOLTS ‘ ” O09—Sayeuyay iesng TermojoD 00°S22°T * ° i. r — 000°I— ated epliejapy 6USPS'T 7 “ QO2—sAnISNpUT payepyosaep ueyensny 08'G0E'T a . ‘ ‘h ia QO00*T—SyHomMoo AA ¥9035 fiunby 00°0060T 00°000'S ‘ 7 os = YoeL—SUOUEM "AON A 00°006. ‘ 7 . : uo * - %B— TT 00°000'S : i. . rby ’ b%eL— VO A OO 000G | 7 : * %4L—IV WO Oo n00r ~~ " . " ~ %g—aouPUTy gytoMsuay psodaq? paxy.y $ $ (3809 9¥) O46T “ANAL MOE LY SLNAWLSTANI 40 ATINGHHOS ce's7ss a! . “ “ QLGT ‘eunf WOS aounjoy survo7/y OS T9L'S STRESS 00'OOL 00°00T + oS " _ 7 paaydays ‘s Q0°00T a _ = yi 7 ~ “ doyteg 'S O0°OST . , a a ° “ pooM "DL 00°0ST " i. * ‘ " ~ SULApOOD “H 'L 00006 “ il a . a is ° aeyied “ad SUD Yaspasay ST FEST O8°ST iC j = ~ SAUKOTPIG; TMOMpOOA OT + PR LES i " saMouyay zesng juMUUjuy OOZ TSStrro | 6IG1F ~ it tf 4 - ' ysasrajuy yueg O0'Sste ie i - eyeysny jo siexeuraqny, OO9 OVPRET - " parsooy Spuaplard pau jsaseyuy tscat . ~ Saysnpuy pojeplyosuoyy uByeusny Z spiaaay ppy ‘ Sjuaiuzsaauy fo asvYyaing Beragert P “ ue G96L ‘AIN[ IS] aounpy Buinado $ SLNUWAVE SLdgoou —eee—vWvvOxv0usssS—————S——<$<———— OL6E “ANN Hoe GHANA HVAA AHL YOA SLNAWAVd GNV SLdIIOAN JO SLNAINGLVLS CNN HOWVASAY DIATLNAIOG (NV LNZWAMOONG CALVYOdUOONI VIIVULSAY HLNOS AO ALAIOOS IVAOY AHL REPORT ON ACTIVITIES OF THE COUNCIL, 1969-70 Summary REPORT ON ACTIVITIES OF THE COUNCIL, 1969-70 Iu the course of the past year twenty new members were elected and one person was re-admitted to membership. Four members died and fourteen resigned so that membership increased by three to the present record figure of 283. In February 1970, the Society suffered a grave loss through the death of the immediate Past-President of the Society, Mr. F. J. Mitchell. The Council appointed Dr. K. R. Miles to fill the casnal vacancy thus created. Eight Ordinary Meetings of the Society were held and attendances ranged from iwenty-one to seventy-eight. The average attendance of forty-eight was the highest in the Society's history. The addresses presented at these meetings were us follows: September 1969: Mr, F, yi Mitchell (Presidential Address); “A biota with- out leaf or relief”. October 1969; Dr. N. I. Ludbrook-: “Ancient cultures. of Mexico”, November 1969: Mr. R. Hope; “Heritable variations in populations of the Brush-tailed possum (Trichosurus vulpecula)”. April 1970: Tho: Society's Patron, His Excellency Major General Sir James Harrison: “The scientist under the microscope”. May 1970; Prof, J. F. Lovering: “Geological history of the Junar surface”. June L970: Prof, A. A, Abbie: “Brachymesophalangy V. in Austvalian aborigines”. August 1970: Dr. A. FE. Newsome: “Mouse plagues: genesis and exodus”. In July 1970 2 panel of speakers comprising Mr. Shepherd, Dr. Smyth, Dr. Womersley, Mr. Thomas and Mrs. Paton, presented contributions on the results uf the expedition to Pearson Islaud. Seventeen papers were read at the Ordinary Meetings, These comprised Boiany (6), Zoology (6), Geomorphology (2), Geology (1), Limnology (1) and Palaeontology (1). Eleven exhibits were also presented at the Ordinary Mectings. Most of these were provided as a result of approaches made by the Council to various scientific organisations. The social function held in June 1970 took the form of an informal dinner held at The Colonial, Glen Osmond. Professor Neal addressed the mecting which was attended by thirty-five members and guests. His uddress was entilled; “Science in the Education of Tuman Beings”, Nine meetings of Council were held Turing the year. In 1970 four awards were made from the Scientific Research and Endowment Fund to assist research being undertaken by members of the Society: Mr. I .R. Goodwins of the Department of Genetics, University af Adelaide was eranted $150 to investigate the occurrence and distribution of the seeding tetraploid Oxalis pes-caprae (common soursob) in South Australia. Dr. T. G. Wood of the C.S.LRB.O. Division of Soils received $150 to undertake a oreo study of raphignathoid mites in the Berlese collection at Florence, faly. Dr. S. Barker of the Department of Zoology, University of Adelaide was granted $100 to study nutritional anaemia in the Quokka Setonix brachyurus, a stall wallaby population on Rottnest Island, Weslem Australia. 253 On behalf of a group of members, Mr. 8. A. Shepherd was granted $100, supple- mented by $150 from other society finances, to assist an expedition to St, Francis Island. Volume 93 of the Transactions was published in December 1969. It con- tained seventeen papers and comprised 201 pages. The Griffin Press again acted as printers, The Library continued to operate efficiently and profitably during the year, permitting the Council to embark upon a programme of reprinting early volumes of the Transactions. Volume 6 has been reprinted by the State Library and is now available for sale. One set of 80 volumes of the Transactions was sold. A total of 2094 accessions were received; 8 new exchanges were negotiated; 366 volumes were borrowed from the Library, mostly on interlibrary loan, and 93 volumes were bound. The Council wishes to express, on behalf of the Socicty, sincere thanks to Mrs. Dunlop and Mrs. Dougall for their service to the Society throughout the past year. M. J. Tyler, Secretary. EXHIBITS I, M. Tuomas: Manganese nodules from the South Pacific Ocean. R. Epwarps: Some preliminary results from excavations of small rock shelters near Beachport. G, Mount: A revised concept of conservative dentistry, I. M. Tuomas: Peripatus in the Adelaide Hills. B. Trams: AMDEL’s role in the field of forensic science. Dr Hy. Eicuter: Some recent plant discoveries, J. Hocan: The asthma weather/spore survey. Dr P. Witson: Development of lungs in marsupials. OFFICERS FOR 1969-70 Summary ROYAL SOCIETY OF SOUTH AUSTRALIA INCORPORATED Patron: HIS EXCELLENCY MAJOR-GENERAL SIR JAMES W. HARRISON, K.C.M.G., C.B., C.B.E. OFFICERS FOR 1969-70 President: Cc. B. WELLS, M. Agr. Sci. Vice-Presidents: K. R. MILES, D.Sc., F.G.S. S. A. SHEPHERD, B.A,, LL.B. Secretary: Treasurer: M, J. TYLER W. G. INGLIS, Ph.D., D.Sc. Editor: Assistant Editor: J. K. TAYLOR, B.A., M.Sc., B,Sc.,Agr. I. M. THOMAS, M.Sc., M.I.Biol. Librarian: Programme Secretary: N. H. LUDBROOK, M.A., Ph.D., D.I.C., F.G.8, J. M. LINDSAY, B.Sc. Members of Council: G. F. GROSS, M.Sc. R. H. KUCHEL, B.Sc. R. T. LANGE, B.Se., Ph.D. K. E. LEE, D.Sc. C. BR, TWIDALE, M.Sc., Ph.D. H. E. WOPFNER, Ph.D. Auditors: Messrs. MILNE, STEVENS, SEARCY & CO. AWARD OF THE SIR JOSEPH VERCO MEDAL Summary AWARD OF THE SIR JOSEPH VERCO MEDAL 1929 1930 1931 1933 1935 1938 1943 1944 1945 1946 1955 1956 1957 1959 1960 1961 1962. 1963 1965 1966 1967 1968 1969 1970 Pror. WALtrer Howcuiy, F.G.S. Joux McC. Brack, A.L.S. Pror, Sm Douc.as Mawson, O.B.E., D.Sc., B.E,, F.R.S. Pror. J. Burton CLeranp, M.D. Pror. T. Harvey Jounston, M.A., D.Sc. Pror. J. A. Prescott, D.Sc., F.A.C.I, HERBERT WomensLey, A.1.S,, F.R.E.S. Pror. J. G. Woop, D.Sc., Ph.D, Crem T. Manian, M.A., B.E., D.Sc., F.G.S. Ilenpert M. HALE, O.B.E. L. Kerma Warp, 1.8.0., B.A., B.E,, D.Sc. N. B. Trymate, B.Sc, . S. Preer, D.Sc. G, Stepnens, D.Sc. Wi. Frntayson L. Specur, Ph.D. G, ANDREWARTHA, M.Ag.Sc., D.Sc., F,A.A. H. F. ie) 20200 Luvaroox, M.A,, Ph.D., DJ.G., F.G.S, V. Soutucott, D.Sc., M.D., B.S., D.T.M. & H, noF. A. R. ALDERMAN, D,Sc., Ph.D., F.G.S, D, Pryor, M.Sc., Dip.For, . C, Spricc, M.Sc, H. B. S. Womers.ey, D.Sc. M. F. Grarssner, Ph.D. (Vienna), D.Sc. (Melb.), F.A.A. For distinguished contributions over a wide range of palaeontological research, particularly in the evolution and morphology of foraminifera and crustaceans, and the Precambrian fossils of South Australia, Major publi- cations include the “Principles of Micropalaeontology”, which has remained a standard textbook in the field for 25 years, the section on Decapoda for the Treatise on Invertebrate Paleontology, and a monographic study of the us ossil Detained Crustacea of New Zealand and the Evolution of the Order ecapoda, Publications with his colleagues on the remarkable Precambrian fossils from Ediacara have been instrumental in attracting world-wide attention to this ancient fauna. The author of over 120 publications, he has also made significant con- tributions to stratigraphic correlation and to the geology and palaeontology of Papua-New Guinea. He holds the position of Professor of Palaeontolagy in the Department of Geology of the University of Adelaide, ‘ , mito bo 256 1970 1969 1970 1970 1970 1970 1969 1969 1970 ROYAL SOCIETY OF SOUTH AUSTRALIA INCORPORATED NEW MEMBERS, 1969-70 sae ab BN ¥., B.A., Geography Dept., University of Calgary. Calgary 44, Alberta, anadd. PREEON, A M., Dept. of Genetics, University of Adelaide, North Tce., Adelaide, >A, 5000. Forrest, W. W., B.Se., Ph.D, Australian Wine Research Institute, Ashton, S.A, 5137. Fuxemay, M, J., B.Sc., 46 Mahood St., Elizabeth Grove, S.A. 5112. Goss, M. L., B.Sc., Flat 4, 10 Da Costa Ave,, Prospect, S.A. 5082, Harnes, A, K., B.Se., Dept. of Biology, James Cook University of North Queensland, ‘Townsville, Q. 4810. Tlanvey. W. J., 48 Westall St., Hyde Park, S.A. 5061. Houmrs, Prof. J. W., B.Sc., M.Sc., School of Physical Sciences, Flinders University, Bedford Park, S.A. 5042. MacFarane, Prof, W. V., M.A. M.D., Dept. of Animal Physiology, Waite Tustitute, Private Bag No. 1, Glen Osmond, S.A, 5064. Martin, Prof. P. G., Dept, of Botany, University of Adelaide, North Terrace, Adelaide, S.A. 5001. Mosxovits, E. E., Dipl-Ing. M.A.I.M.M., 29 Wellington Tce,, Fullarton, S.A. 5082, Nicwouas, Prof. D. J. D.. M,A,, Ph.D., D.Se., Dept. of Agricultural Biochemistry and Soil Science, Waite Institute, Private Bag No. 1, Glen Osmond, S.A. 5064, Oapts, J, M., B.Sc, Ph.D., Dept. of Agricultural Biochemistry and Soil Science, Waite Iustitute, Private Bag No. 1, Glen Osmond, S.A. 5082. Paton, Mrs. J. B., M.Se., Biochemistry Dept., University of Adelaide, North Tce., Adelaide, §.A. 5001. Puepce. N, S., M.Sc., South Australian Museum, North Tee., Adelaide, S.A. 5000, Smaru, B. H.. B.Ag.Sci., Ph.D., C.S.1,.R.O. Division of Soils, Private Mail Bag No. 1, Glen Osmond, S.A. 5064, Stewart, ANN M., B.A., A.L.A.A, 48 Narinna Ave., Cumberland Park, S.A. 5041, Watcace, H. RB. PhD., DSc, C.S.LR.O, Horticultural Research Division, Waite Road, Urrbrae, 8.A. 5064. Watts, C. H. S,, B.Sc,, D.Phil., Institute of Medical and Veterinary Science, Frome Rd., Adelaide, S.A. 5000. Wison, M.B., B.S., Dept. of Human Physiology and Pharmacology, University of Adelaide, North Tce,, Adelaide, S.A, 5000. CONTENTS Brian McGowran: Late pence in the Otway Basin: biostratigraphy and the ageof key microfaunas- = - - = -~ = “=~ "~ - Crare R. Murpny and Janice R. Smrru: Age determination of pouch young and juvenile Kangaroo Island wallabies - - - - "= = F. Desrenne: A revision of Australian genera of Archaeocyatha- -~— - Ronert F. G. Swinsourne: A new species of Pelargonium L’Her ex Ait in South Australia - - - = 2 A : S é C. R. Twmaze, JENNIFER A. SHEPHERD, and Rosyn M. Tomson: Geo- morphology of the southern part of the Arcoona Plateau and the Tent Hill region west and north of Port Augusta- = - = = = = = A. Taruty: Physical and chemical limnology of the Blue Lake of Mount Gambier, South Australia - 2 = : = if x Fi A, Mary Wave: The Stratigraphic distribution of the Ediacara fauna in Aus- A ee a ip i Lota STE Ta, er a ee S. A. Suepnerp and H. B. S. Womerstey: The sublittoral ecology of West Island, South Australia: 1. Environmental features and algal ecology - S. A. SHEPHERD and JeaNeTre E. Watson: The sublittoral ecology of West Island, South Australia: 2. The association between hydroids and algal substrate - - - - - - - - - - - - Harotp W. Manten: A new genus of Trematode (Digenea; Gorgoderidae ) Sars the ureter of the tuna fish (Thynnus thynnus maccoyii) in Aus- SEATAY Sa 2h we, Nardi ops Fa oe oe ce a ee ok Wiu1aM J. Stuart: The Cainozoic stratigraphy of the south eastern coastal area of Yorke Peninsula, South Australia - é ¥ = - “ Susan BARKER: Quondong Station, South Australia: a field context for applied rangeland research- —- ee 8 a een a ee B. P. Tuomson;: A review of the Precambrian and lower Palaeozoic tectonics of South Australia - 2 : = = - a a e . Parricta M. Mawson: Skrjabinoptera goldmanae n.sp. (Nematoda Physa- lopteridae) from an Australian Agamid lizard - - = -— - R. F. Parsons: Mallee vegetation of the southern Nullarbor and Roe Plains, Australia - es. . ee i : ee J. R. Maconocmne and R. T. LANCE: Canopy dynamics of trees and shrubs with particular reference to the arid-zone topfeed species - - - Obituary: Francis John Mitchell, 1929-1970 - - fi 2 2 z General Account, Library Account - - - - = = 7 = Endowment and Scientific Research Fund- = - - = = = = Report on the Activities of the Counc Re) xi eth et ae ee Officers for 1969-70 - . = - = 2 3 z Bg ft Awards of the Sir Joseph Verco Medal 1970 Te